The economics of restaurants are pretty unique. I'm all for not tipping and paying a normal wage to wait staff but picking out restaurants fail at an incredible rate.
Using Waffle House as an example is hard because it's a private company but food service profit margins aren't typically super high. A Waffle House, in a good location, I'm sure makes a good amount of money but the owners of those restaurants are often the hardest working employee there (and they are there, at least in the beginning) if they are going to succeed. Plus, those owners have loans to pay off at the beginning. It's a tough business.
There's more I could say but, the TL;DR is that most businesses aren't making the profits of a Google or Apple and don't usually have tons of spare cash around to give everyone a raise, as much as most (small) business owners would like to. Especially newly established restaurants, paying off business loans takes a big chunk of the revenue.