Someone was asking about why the restaurant tip is a percentage of the bill vs. a per head price...There are a few reasons for this but it falls down to keeping the tip proportional to the bill.
So if I go to a low cost restaurant (Diner or Chain) there will be one server + maybe a bus person (the person who runs around and clears tables and sets up for the next use) I’ll be there maybe an hour and my bill for 4 people may be about $30. Tip would be $6. The server will likely have about 5-10 tables they are serving for at the same time.
On the other side of the coin if those same 4 people go to a nicer restaurant...
There will be alcohol likely, the server usually has support staff to help them including the bartender, an ass’t to run food, as bus person to set up tables, etc. We’re going to spend several hours at the table and have multiple courses. To have time for better service the server will have less tables 5 max, and less turnover in the night. So maybe my bill is now $300 so the tip will be $60. (Likely more since the team would have given excellent service) Out of that $60 the server then ‘tips out’ their support staff, but the server will keep the lions share. These servers are also the more experienced ones who excel at their jobs.
Generally people start serving as a part time after school job in the smaller not expensive restaurants, and then if they decide to stay in the service industry they move on to nicer restaurants where they can earn better tips. This no different than anyone else starting at an entry level job and moving into bigger and hire paid roles.
I’ve known a lot of servers and bartenders and none of them want to move away from tips. They make far more money than they would with a flat wage.
Think about it, even at the lower end restaurant making a tip of $5/table. All it takes is 2-3 tables an hour and they’ve made more than minimum wage.