I feel like there's a lot more to Kaoru that the manga doesn't show. You have to be really hard working and dedicated to get to the top of any industry. He even left the porn industry and made it as an author so he probably has really good business sense. The manga probably just showcases him as shallow because autobiographies about hard life don't sell and it's easier to grab an audience who normally won't be into reading about girlyboys with a comedy.
He was the 1st crossdresser without any "changes" like estrogen or operations , that's what made him popular in the industry. He scalated quickly on the top porn company and made sweet sweet money until he decided to quit with the job.
I agree that being unique gave Kaoru's career a boost, but the only we reason why we know about this unique fact (that he doesn't take estrogen) is because someone (Kaoru, his management team if he has one, or his company) made this part of Kaoru's brand. Part of business sense is knowing how to brand yourself.
Kaoru's decision to transition from gay porn to straight porn was a business move. Professionals don't switch their filming genres without considering the impact it would have on their careers, especially from a genre that's typically more profitable for male actors like gay porn. Perhaps Kaoru assumed (correctly) that the switch would raise his profile.
That he was able to later transition from niche TV (porn) into more mainstream TV instead of retiring is no small feat either. Overall, porn is an industry with a high overturn rate. Many professionals reach the end of their careers by their mid to late 20s. Some of them start businesses and branch out into other media careers after the porn industry, but not all of them have staying power. While it remains to be seen how long Kaoru's profile will last, that he's able to find a publisher to distribute a niche-genre manga is good news. It means that a publisher believes he has a decent sized fanbase and that they can be monetized (aka interested or loyal enough to buy his work).
Many people have pretty faces and unique factors in the entertainment industry, but whether they endure for as long as Kaoru has depends on how well they market themselves.