The article claimed that modern diets don't put enough strain on the jaw in childhood, so the jaw doesn't grow as much and there's more crowding. Has nothing to do with protein intake.
Meat is easy on teeth, what traditionally wore down teeth in human history were rough unprocessed grains, tough vegetable fibers, nuts, and the use of teeth as tools (working plant fibers for example). Of course the inclusion of sand or grit in food also contributed. People also chewed a lot of bone in history, either whole or as with Aboriginal Australians, as a mash of whole animals.
