It strikes me that if we started paying a normal wage for waiters and waitresses, it would be a net negative for the workers, a net negative for non-tippers today, and a net positive for those who do tip 20-25+%.
The help would almost assuredly make less money, with a fixed rate and no tips, and taxes taken out of a w2 check, and they probably will only be able to work right up to the limit of whatever full time is defined as to get away with having to be given benefits or whatever.
Non-tippers would be paying more as their per unit cost would be higher (because they are horrible people who don't tip) as the restaurants entire menu would necessarily be raised across the board to accommodate and soak up the upfront sunk cost by the business in having to provide a $18/hour + meager benefits. Your $10 cheeseburger is now $16 or whatever, as an example.
The diner who tips moderate to exceptionally will win. We expect to pay 20-25+% on our ticket and so the final bill with the adjusted prices, unless 20-25% higher than otherwise, should be lower.
But the reality is, we keep it at $2.13 because servers and bar tenders and patrons like it that way. They like making gobs of cash (in good situations, at least) that can minimized on taxes, and if made to be another rote employee that a robot could do, the incentive for good service would go away and you'd have even less people wanting to do this job than we do today. Also, just speaking for myself, but it makes us feel good to be a good tipper. I tip 100% at waffle house because that usually only amounts to like 15 or 20 bucks, and you'd think I was a hero. It makes people's day and the people working at waffle house are exactly the type who need the blessings.