once you sell your soul (and vagina) their ain't no going back
No. That is isn't it.
As with any high income job, once you become accustomed to a certain standard of living, the natural desire is to maintain it. However, as with other low skilled workers, your average prostitute wouldn't be able to compete in the market place and maintain their current standard of living. If you could, you wouldn't have decided to suck cock for a living. And yes, I do not underestimate that it is a decision that a great many women take lightly. I strongly suspect that it's primarily a decision based on need, rather than a totally free choice. That's certainly my perception from talking with a great many prossies, post punt.
Less you forget, the same 'idiot' who cannot follow your simple directions, is the customer, whether you like it or not. To put it bluntly, no idiots, no £600 spending spree in Selfridges for you and you'd probably be on minimum wage, if you're lucky.
Nobody said that prostitution was easy, but nobody forces you to do it and you always retain the right to turn away an undesirable punter. Compared to a nurse, who undergoes years of training, is skilled and also puts up with abuse, both verbal and physical, in addition to cleaning up patient's piss and shit, on occasion at £18k a year, you have it easy, so I have little sympathy for you.