The shops I use recently, are 2-3 bay father and son operations, plus another fellow, or an apprentice. Small town shops with their names on building and the owner is turning wrenches. They aren't wrecking themselves, and cutting corners, trying to jam through as many cars as they can in a day and beat the clock, or charging the so much that they don't have a long waiting list. They are doing it because they like fixing stuff, and charge enough to have a few toys and nice vacation.
You can watch through the open shop door if you like, and they sure aren't slow, and they charge a fair price.
They do undercoating, and I listened to him tell a customer on the phone, to drop off the car this afternoon, they will pressure wash the underside, and then leave it in the shop to dry, so they can spray it in the morning. So they seem to want to do the right thing for to keep their long term customers.
I guess with little overhead, they can charge 8-10hr each a day, and go home with most of it, so its certainly working for them, and for me. No dealership fees, franchise, advertising, website, mortgage, etc.... No free coffee, but you can look at his collection of old interesting mechanical stuff for free!
4.9 of 5 google reviews too, so its not just me who like their operation!