Studies? LOLOL.
I don’t know if you’ve ever worked in a kitchen before, but even if you’re eating at a top TOP restaurant, the dude plating your salad (see:uncooked food, most important) is only getting paid $7-8/hr. Doesn’t matter if you’re paying $5 for a McDonald’s salad or $24 for a walnut pear and soft goat cheese salad.
Edit: Also, just because someone gets paid $200k a year doesn’t mean they give a shit about anything.