Most of the higher end ladies (and all the ladies I associate with) have been in the industry at least a decade. It takes about that long to really hone your craft and to become an exceptional courtesan.
Many of these ladies have changed their name or location, or gone under the radar for periods of time. However, the same adage applies to this industry as all others. "It takes 10,000 hours of hard work to look like a overnight success."
I have heard of very few ladies who have been in this industry for 3 or 4 years. It's either a couple of weeks or months, and they realize it isn't right for them, or it becomes a career, with breaks to have children, or start up other businesses.
If you love being a courtesan, it's not about the money or lack of alternate employment. It's about the art of sensuality, healing, and deep, genuine connection. It's either in your blood, or it isn't.