I feel its important to point out that for many in the service industry, its not necessarily seen as a minimum wage job, its a career - and its one of the few careers that you can make very good money in without an education behind you.
All in all the culture here in the US has permitted it to morph into the monster it currently is where every Tom, Dick and Harry who hands you a coffee cup is conditioned to expect 20% from you on their Square terminal.