Many of these brothels are out in the middle of nowhere and the girls either live near there or commute -- either way that's not conducive to attracting the hottest girls around. The girls that work in the urban areas, even though there are laws preventing it in such places, are able to do other things besides prostitution. In Vegas, the really hot girls are strippers or exotic dancers and some of them will freelance as hookers part time.
Vegas is an interesting place and having lived there for a year I came to understand a dynamic that takes place. The top clubs attract the hottest and youngest girls and the girls can make a ton of money, often times several thousand a day, at these clubs. But, by the time they're in there mid to late 20's they're being pushed out the door by the newer younger girls and they either get out of the business at that point or move to the second tier clubs that pay less. Sooner or later they are no longer viable at these second tier clubs and once again they either get out of the business or they move to the third tier clubs further away from the strip.
By the time they've moved to the third tier clubs they have almost certainly gotten breast implants and other surgeries and are getting to look pretty rough. I used to do my laundry at a club along the Boulder Highway area as they had, in addition to a bar and mini casino, they also had a laundry. I'd put my clothes in the machines then go into the bar for a beer or two as I waited for my clothes. It was a common sight to see women in there late 30's or 40's with generally slim bodies and very obvious implants but also with that 'rode hard and put away wet' look to them. By this time they had pretty much become prostitutes.
So, no matter how pretty they were when they got into the business in there late teens by the time they were in there late 30's they'd been worn out big time. The girls that do it for a few years then get out can have fond memories but the ones that stay in probably don't.
Brian