Earlier quoted context omitted.
This has been tried many times, you are ignoring the reasons it did not work. The employees hate it because they make less money, forcing the restaurant to go back to tipping. It was effectively a pay cut for employees. It is not wage/revenue neutral because it changes customer behavior. Generally speaking, Americans are more generous when the money goes to directly to a service person than to a faceless business tha…
How much money did they make with raised wages and no tips? Was the wage still not comparable to other jobs?
One reason several of them have mentioned is that many customers are happy to regularly tip much more than 20%, and this is often correlated with the highest spending customers. Making it a non-discretionary 20% puts an artificially low cap on how much they earn from the customers that pay the most. At one time some customers would leave extra cash on the table after paying the "no tipping" bill, but no one carries cash anymore.
Places that net $40/hr have enormous difficulty hiring right now. These are not poorly paying jobs but the broader lifestyle is pretty terrible even at good restaurants, made even more terrible because of the employee shortage.
One overlooked issue is that many restaurant workers in the big cities are originally from "flyover country". When the restaurants closed during COVID, a large number went back home. I was talking to a waitress in the middle-of-nowhere Iowa a few months ago and she had just moved back after several years working in New York City restaurants.