Mileage will indeed vary. It’s never taken me more than 10 minutes to thoroughly brush a large, hairy dog - as long as that dog’s coat hasn’t been neglected and formed tangles or mats, that is. If it’s a shedding breed it’s best to do it outside, it can be an impressive mess especially at certain times of year.
Heck even currying and brushing a big dirty horse only takes around a half hour.
BUT I am poor. If I had money I might just hire groomers.
Emphasis mine. Some dogs will bark non-stop when left alone, out of nervousness. Crating mitigates this to some extent, but not totally. If your schedule varies, your dog may be barking at times that will annoy your neighbors. I am sure you have experienced this - an all-night bark fest. If your neighbors are not dog people, they will blame the dog, but if they are dog people, they are going to blame YOU.
Based on what you (OP) are saying so far here, I have to agree with the other posters recommending you not get a dog - to be fair to yourself, the dog, and the neighbors.
Oh, dear. That sounds dangerous for ANY pet (or child) although I’ll admit curiosity at how a fence is “[not] really practical” in that situation.
Not to stop a dog running full-tilt into a busy street, no. “Something to think about” in that case would likely be contemplating the image of a bloody mangled mess.
How is that relevant to dog ownership?
You guys are spending too much time on the garage thing. I mentioned it as a possibility. If that isn’t optimal, than I won’t do it.
Perhaps, but their excrement is going to need regular maintenance or else expect the place to start smelling like a dog kennel.
Nearly all dogs have personalities like little two year old kids, and are nearly always in constant need of attention. By yourself, that dog isn’t going to be getting much attention. I’m sure some breeds are better than others, but don’t know which ones. You willing to get two dogs would help here, but mean more work for you too.
As another suggested, a cat might be the way to go. They can be affectionate, but at the same time, they don’t seem to give a shit if you give them attention or not, and are quite content with you being gone long periods of time out of THEIR house most of the time. 
I managed to rescue a baby wild black cat out of my old factory many years ago, and gave it to my parents on the ranch. Mean as hell, and it took us several months before it ever decided to have anything to do with any of us. Damn near a half a year actually, he was that mean and wild. I wouldn’t have had him any other way though. When I grabbed it out of the box, I had two pairs of cotton gloves on, and he still bit through and drew blood. I loved his fighting spirit, and was also quite the gopher killer. Even when I visited my parents though, when he spotted me from a distance, he would make a run for me, and jump right above the boot, and bite down just as hard as he could. And yes, he still could draw blood. What an ingrate! But that’s just how he played. He wouldn’t do that to my parents though.
All I’m saying is not to get an unhousebroken dog with the expectation that the garage will solve that issue. Get an adult dog that is housebroken already and leaving it alone while you are at work shouldn’t be a huge problem. Lots of single people have dogs and work. As long as you take it on plenty of walks before and after work, it will be fine.
A cat is no substitute for a dog.
Gee, I know, how about a fish? Or a plant? They’re a lot of fun.