I know I’m drifting a bit off-topic but, like @QuickSilver I wish we had a few shooting brake options here in the US. I currently have a 2009 Volvo C30 that I love to death and will drive into the ground. My ideal replacement would be the same car stretched by 2 feet or so into a shooting brake configuration but, alas, there’s nothing like it on the market in the US right now (at least, not that I’m aware of). Even the “hot hatch” market has shrunk. So, like I said, I will drive my little green Volvo until I physically can’t anymore, and then maybe I’ll find a used one and drive that. 
Because most people don’t use cars that much to move things, but to move people.
My car with a trunk has rear seats that fold down, so I can carry long loads. The only advantage of a liftback would be if I were to have a large boxy item that would require leaving the liftback open while I drove.
A liftback requires that the car have extra (heavier/costly) reinforcement elsewhere to regain the stiffness lost from the large opening… A car with a trunk has the package tray running from one side of the body to the other. The liftback is more likely to move around as the body flexes - more customer complaints from squeaks and water leaks.
One of my previous cars was a hatchback and any noise from the rear came right up into the passenger compartment. The enclosed trunk offers better sound reduction.
I’m one of the those super weird abnormal people who think of cars as machines that carry stuff from one place to another – and that is it, period, nothing else. No romance, illusions of safety, aesthetics (when am looking it? Never) thrill of the road, status signalling, or any other crap.
The car that does that the most efficiently and easily is the car for me. I have a full size 4wd pickup for the farm, and an old Honda Fit for everything else. Fits are great cars: carry a huge amount for their size, nimble, efficient, well-made. I don’t understand why everyone doesn’t drive subcompact hatchbacks.
For those confused about what exactly a liftback is, the first gen Mazda 6 was available in 3 body styles, a sedan, a wagon, and hatchback. You can see the wagon in the background of that picture, it’s what people typically thing of when they think hatchback, wagon, SUV – a vertical opening. The hatchback pictured (foreground, with the trunk open) was sometimes referred to as a liftback, or in the 70s/80s, a fastback. Here’s the Mazda6 hatchback with the hatch closed. It looks like a sedan. And here’s the mazda6 sedan with it’s normal trunk opening.
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Externally, the only difference between the sedan and the hatchback was that the hatchback had a rear wiper and the sedan didn’t. The profile was basically the same, and you wouldn’t know how big the “trunk” opening was until you walked up to it and opened it.
As far as the question posed by the OP, I think the only practical difference is that a sedan allows the trunk space to remain secure and separate from the rest of the car. You can quibble with this as the actual benefit is questionable, but I’ve heard this as a reason people want a sedan instead of a hatchback. Other than that, sedan buyers are a dying breed and everyone else wants SUVs/CUVs now. Hatchbacks are seen as “cheap”. And it probably costs more to make a liftback than a normal trunk, so if customers aren’t demanding it, automakers aren’t going to build it.
As an aside, all of these terms are nearly meaningless as automotive marketing wizards blur the lines: sedan, coupe, hatchback, liftback, fastback, wagon, sport wagon, sport utility wagon, sports activity wagon, sport utility vehicle, crossover, crossover utility vehicle, etc. If Audi and BMW can make 4 doors with trunks and call them coupes, these definitions have lost all meaning.
The real advantage is how much easier it is to get large and awkward items in. I had a saloon once and I wouldn’t get one again, but they’re pretty uncommon in the UK anyway. A hatchback is the standard car here.
I’ve heard that, too. People feel like they can leave their purse or laptop in the trunk of a sedan and it’s out of sight, and at least a little harder to get into.
I’ve had a variety of cars, including sedans, hatches and wagons (estates). The noticeable difference I have found is that sedans tend to be slightly more luxurious in the sense that the cabin is more isolated from cargo noise. I’ve had a top of the line Volvo V70 Turbo wagon that was a brilliant car but the noise from the cargo area was a constant and mildly intrusive. On the other hand, my current German sport sedan is very quiet. My wife’s German sport hatch (coupe) is a brilliant little car but again, noise comes from the cargo area. Worst car I ever owned (briefly) was a Jeep Wrangler, which was like driving an old barn in a storm.
Here’s a 1976 Toyota Celica Liftback. ISTM that it would be a pain to load the back, having that lip still there.
https://www.cargurus.com/Cars/1976-Toyota-Celica-Pictures-c4191#pictureId=13508227
Wikipedia says:
The Toyota Celica Liftback GT won Motor Trend Car of the Year (Imported Vehicle) in 1976.
Whomever is keeping the official list, add me to it as one who still does not understand the difference between hatchback and liftback.
I’ve read the thread and clicked on all the links. Twice. 
mmm
OK, I just found this:
I think I was confused because what is now known as a liftback was called a hatchback back in my day.
mmm
Seems like the worst it both worlds. If you want a hatch get a hatchback. If you want a sedan then get a sedan. Why would I want a car that looks like a sedan but has a less effective hatchback? Kind of like why El Caminos didn’t work.
That seems to be more of an artifact of marketers and buyers not wanting to associate themselves with a notion of “hatchbacks” as econoboxes or small sports coupes.
The “liftback”’s lack of popularity in the US may have to do with seeing it as a solution in search of a problem. As has been pointed out, the sedan style itself has been dropping in share, with Ford and GM simply surrendering the US family sedan market to the imports. Station wagons (estates) have themselves hardly been seen in this market since the early 00s, either.
The amount of demand for something that looks and drives like the sedan, but just has a much wider rear opening, is just not there. Yet, as observed, when you style the sedan to have a sharply raked fastback so there’s only a tiny rear deck for the trunk lid, and the trunk becomes this hard-to-access cave, that’s annoying and impractical. And still it is apparently the decision of the car buyers out there that if they want practicality they’ll get a “crossover”, built for it.
ETA: good observation from Loach on the disappearance of the Ranchero/El Camino-type vehicles. The market attitude has evolved into: You want to haul? Get a hauler.
This. I’ve mostly bought hatchbacks, until my most recent car, when i needed more hauling space, and bought a small SUV/crossover.
(I used to have a minivan and and a small hatchback. That was great, but our habits are a little different now.)
That’s what I was going to say. I think the reason for the confusion comes from the fact that at least in the US nearly everyone just calls them “hatchbacks” and doesn’t really differentiate them from liftbacks.
The term isn’t really new, though. As with the example of the Celica above, Toyota seemed to like to call their cars “liftbacks” back in the 1970s and 80s.
Another example of a liftback would be the Honda Accords of the 1970s-80s, although I think Honda just called them hatchbacks (thus adding to the confusion).
I can appreciate why an El Camino falls well short of the utility of a pick-up. But I think you’re underestimating the utility of a modern liftback like the Audi S5 Sportback or Kia Stinger GT. I’ve got a similarly sized MB sedan and find that getting stuff in and out of the trunk would be easier if the trunk and read window opened as one single unit (aka liftback). Additionally, and most importantly, utility improves when you put the rear seats down in a liftback compared to my sedan. Why don’t I just get a hatchback or a wagon? Well, because I wouldn’t have a sedan.
That’s probably a big part of it. When I had my hatchback (or liftback?) a big problem I had was that everything was always in view. How do you stop at a store when you have a $1000 purchase from Best Buy in the back with no way to hide it? Plus, the sun beating down on everything caused some issues. Over the years, a good number of plastic items I had in the back would end up warped. I eventually kept a bed sheet back there that I could toss over things to keep them out of view and out of the sun. Don’t get me wrong, I could get bigger stuff back there than I can with a similarly sized sedan, but it had it’s share of issues.
And, yes, SUVs have similar problems with people being able to see in, however, with the higher, and often tinted windows, you really have to get right up to the car to see what’s back there. With a hatchback, you can see in just walking past it.
I was concerned about that too, so after I bought a Honda Fit hatchback, I bought the cargo cover through the dealer. I’m sure such things are available for most hatchback and SUV models.
I don’t know if it was available for my car (Honda Insight), but it is for a lot of SUVs. I never knew what it was until I asked a friend that sold cars for a while what the “privacy cover” option is that I always see mentioned for SUVs. She told me it was exactly that. A retractable shade that goes from the back of the rear seat to the lift gate specifically so you have a spot to hide things.
Of course, if you do that, like having something obviously covered in your hatchback, there’s always the concern that someone will break the window to see what it is. If it’s nothing worth stealing, they’ll just move on.
Just like at my store. At night we leave the registers open. We do that so if someone breaks in, they don’t then go and pry the drawers open (or steal the registers) to find nothing in them. We also have a case with a lot of expensive stuff in it. We always kept if locked to keep shoplifters away from it. We learned the hard way to unlock it at night so the burglar can empty it without smashing the glass doors.
Mine isn’t retractable. It’s rigid but with a hinge section that raises when the hatch is opened. And by the way, unless I’m carrying something where the cargo cover is in the way, it’s always in the back of the car, whether or not I have something valuable back there.