I doubt very much typical wait-staff in Bangkok are making 25K a month with tips. Perhaps at high end or very busy tourist places, but that is certainly not the rule.
Happy-ending massage joints sure, but I thought we were talking about restaurants. How many customers a day does the average massage gal get?
Minimum wage for a full-time employee in Bangkok is B11,160++.
In the US? No, that is absolutely not typical.
You said: "I understand the concept of wanting to tip, but being socially expected to do it is just dumb.". When I asked why, you answered: "Why should society expect you to pay more regardless of service standards?" which does not answer the question.
The whole concept of tipping is to reward good service. Tipping the same regardless of the quality of the service is stupid.
That there are weak people that feel obliged to leave something regardless of the quality of service is ruining the whole concept.
And no, it is not common that restaurants in the US compel tipping, but many do when you have a large group. Again, this ruins the whole concept.
I feel no shame when I am poorly served and leave no tip, nor do I look down on people that don't tip.
People that tip poor service are stupid, and it's not fair to the hardworking staff the provide good service.