You dont have too, the time investment is minimal,many girls were already taking erotic pics anyway. If you are attractive you can ride that wave for several years and keep living your life normally.

I've noticed that many of these girls are college students and the money from their admirers is useful to buy clothes, gadgets and to take their boyfriends to fancy vacations.

So as long as you are aware this is a bubble you will be doing fine.

I don't know what you mean by 'you don't have to.' The claim above is that there is a difference between learning how to program and having an onlyfans account. Your response was to say the difference is that the latter makes money. My response to that is the former is more likely to turn it into a career. I don't see where compulsions come into it.

You dont need to invest time in onlyfans. It's free money basically. For all the other 'careers' , Youtubers, modelling, acting, singing, there is a huge opportunity cost because you have to invest a lot of time just to have a slim chance. If you are 20 yo attractive girl, you take some pics every other day, the less clothes the better and you may be raking money in the thousands by month. It's your choice what to do with the rest of your time.

Turning it into a career is difficult, not because it's hard to get into. Rather it's hard to stay there because your attractiveness is a finite resource that is running out eventually.