I think a big factor is that a lot of restaurants in the US are throw-away businesses. The average life span of restaurant is five years. A lot of people enter the restaurant out of a weird desire to create something - which is to say they're shoveling money into the business 'till they're out of capital and then another "entrepreneur" takes their place. And oppositely, landlords and local government pretty expect that the sequence of failures is going to continue. Everyone else (landlords, restaurant suppliers, consultants and so-forth) makes money.

But watch out for technology and automation...that is the part of the equation that has been "solving" the labor problem for some time now...

Restaurant is a little bit convenience but mostly entertainment. If a robot is going to spit some stuff for you, why not buy an cheaper even microwave dinner, they're not that bad (or cook it yourself for something good tasting and which you can entertain yourself with).