Many people desperately want to be artists. They may go to college and study Art. But the world only needs so many artists. So, if they don't have any other skill, these people inevitably find employment making a low wage in the service industry.
You're completely right. There are lots of these people. I simply do not believe that this number is large enough to significantly alter the analysis I have offered.
Am I generalizing? Of course I'm generalizing. There's no other way to meaningfully talk about tens of millions of unique, special, individual human beings.