As there is no culture of tipping there, potential employees don’t have the same opportunity.
In North America, wait staff have two options. Restaurants where they work for tips and restaurants where they don’t. Logically, they’ll choose the ones that pay more, which are invariably the ones that work for tips.
This is why European wait staff make an average of 12 euros and North American wait staff make vastly more.
I don’t recall a recent meal where I haven’t tipped more than that, and the staff will have several tables.