I think 9 times out of ten the bar girl was a slut before moving on to being a hooker.
The town bike who got pregnant to who knows who, and now is now a single mother that no Thai guy wants, so they hear about how some farangs have fallen for others, so they pack their bags and head to pattaya, Patong etc.
Girls with self respect dont end up working as prostitutes. They do what the other 99% of the population does and get a real job. It takes a certain pesonality to rent out your genitals to hundreds of autistic like foreign men, twice their age and three times their weight.