This is very interesting. In some ways the porn industry mirrors mainstream Hollywood where male actors have a longer potential career than most actresses do. This is because mainstream Hollywood movies are generally also selling sexual fantasies as well. The reason for the turnover (no pun intended) of women in the industry is that the basic male fantasy is to have lots of partners and to have new partners. The basic female fantasy is to have that true love and the all-consuming attention from the man who provides it. Hence men like Sean Connery or Bradd Pitt etc. can continue as leading men for decades.

As to women who escort having peak earnings in their 20s, besides the fact that most men are shopping for sex based solely on looks, don't you think that there is also the fact that younger women are stronger physically and more resilient emotionally to be able to handle these kinds of relationships?

I know one woman in her 50s who was still doing well in the industry but the volumes she was doing was clearly having a profoundly negative effect on her psychologically. You can categorize it as 'work' but there is still a highly personal interaction that takes place and younger women simply bounce back better. However, as you rightly say these types of interactions over time can also cause someone to crash and burn, though I do think that there is a correlation in that regard to how much one is doing.