Unless there are significant monetary incentives involved... Why does he need helping hands, like viagra and dick injections to stay hard do you think?
Is it really that hard for you to believe that a broke good looking straight guy, who is sick and tired of being poor, and who, oh I don't know, wasted his opportunity to get a higher education, or maybe never had the opportunity, or doesn't have the patience, the drive, the smarts or the perserverance to become successful the "noble way", might just be tempted to do something like this to become wealthy? Maybe you've never felt financial struggle and desperation, I don't know, but as for what content that sells the most on onlyfans, there is no doubt that those guys who do gay porn, generally makes more money than straight porn actors and solo performers.
I have been able to persuade straight guys too fool around with me for as little as 50 dollars. The most I ever paid was 10k. Actually it was even more than that, because I flew him out and paid for his accomadations too. It is often possible to get what you want if you are willing to pay for it.