Good for her, but arguably it’s not supposed to be a high paying job. A living wage, sure, but higher than a job that you presumably studied for and required relatively uncommon knowledge seems wrong.
So I guess the answer is no, we wouldn’t expect restaurants to work out how much people get paid in tips and match it, it would be a liveable wage and if the current workers don’t like it they would leave.
I don’t know that your girlfriend getting bankrolled is common across the industry either, tips rely on high traffic and customers with big pockets. Most wait staff don’t brag about how rich they are.