There are laws in place for service workers related to minimum wage. The employers have to make up the difference if tips don’t meet the rate for hours worked. It seems to me that’s not sufficient for the times.
Hypothetically, if everyone were to stop tipping in the U.S. would things be better or worse for workers? Would employers start paying workers more?
The main reason is that it shifts payment of the wait staff to the customer, not the employer. That means the employer has less payroll, payroll tax, etc. and pockets the difference.
It’s a financial motive, not a classist one.