I think part of the problem is that the technology isn’t really developed quite like many people would want it to be.
My MIL’s SUV has a HUD, and when I drove it, I didn’t really care for it. Not because I’m against HUDs or anything, but because it was displayed down low on the windshield- maybe 10 degrees above the angle that it takes to just look at the gauges.
So I was still looking down, just not quite as far. I’d have preferred it to be more like the flight-sim HUDs I’ve used - compass heading across the top of the viewing area, speed on the left, and maybe the gas level and water temp on the right (instead of altitude). That would have required projecting onto an area probably 2-3 feet wide, and 2-3 feet tall though, which might be beyond what they’re currently able to do. Or maybe less, if they can track where you’re looking and display it there automatically.
Another thing to consider is that with analog gauges and enough experience with a vehicle, you can keep an eye on the needle position of the speedometer without actually having to look directly at it. For example, on my truck, 60 MPH is vertical, 50 and 70 are on either side about 10 degrees off, 30 and 80 are about 20 degrees off, and so forth. So if I’m driving, and I’m looking at the road, I can still see where the needle is in rough terms, at least in the somewhere between 30-40 range without having to actively look at the needle and the scale behind it.
Most of the rest of the instruments are not actually critical in-the-moment. I mean, I have a tachometer, but I also have an automatic transmission, so I don’t care much about it. The gas gauge isn’t something I have to look at particularly often, and the same for the water temperature.
So in a sense with the speedometer needle, I’ve kind of got a HUD already.
Now if they could integrate it with your navigation and do some AR-type stuff, that might be cool. Like show the route superimposed on the road in front of you with turns, and what-not. Or showing school zones as say… purple roadways when they’re active or something like that. Speed traps up ahead would be nice too.