It's look more like your too envious to understood.
You claim that going through college can be a passion, but deny me the right to already know that and have included it in my answer, WTF man :/ But more than that, I find you relatively insulting here. Assuming that I put in opposition both going through college and giving up to your passion, like yourself did in your initial comment, is an implicit assumption that games authors haven't gone through college.
But the fact is that there's no magic here. You can't drop-out to succeed in the adult game industry. You need a lot of knowledge, more than one can generally acquire. You need to be an efficient coder, have a strong background in game and UI design, be an artist, and be a good writer. You need to have followed three, generally opposed, curriculum (scientist for coder, artistic for the game design and the CG, and literary for the writing part) to do it by yourself.
Those who succeed are better than you and me, and they deserve what they earn...
And that's where you totally misunderstood me. Giving up to passion doesn't mean that you let down everything and live a lazy life. It's the opposite, it mean that since that instant, you'll dedicate all your live to your passion ; that this passion will pass before (almost) everything else. And despite everything you can think about them, that's because they did that, that they are now successful adult game authors.
As successful as you could have been if effectively you'd gave up to your passion for college. Simply because you wouldn't have ended being one among many, you would have ended being the one. And whatever your curriculum in college, when you're the one, you succeed... But, more importantly, you don't envy the other, whatever how much they can earn compared to you. You don't envy them, because you have the life you wanted, and nothing, absolutely nothing, can't compare to this.
You dont need to invest 5 years to make 30k from porn.
Then, why are you still writing here ? You've gone through college, so you're better than them, right ? And you have a loan to pay, you need this money more than them, still right ? So, go for it !
Since you're sure at 100% that it's easy, it need no knowledge and you don't have this much works to do, what are you waiting for ? No more excuse, go for it, become the new DarkCoockie...
Given all that, I would say that in Northern / Western Europe, you need at least $7000 / month (= E 6100) to have equality with what you'd normally make as an employee programmer / graphic artist.
Since here, France, in this case around 50% of your income goes to taxes, insurances, etc., yeah, it's more or less that.
And if you do it as a team, everything changes again, it becomes easier to do it part time, but you also need to share the income.
Not only you need to share the income, but depending of the country you can't do that without creating a entreprise(-like) structure. This imply that, due to this, the owner of the Patreon account have others expense to add to the ones talked about above.
The few on top of the list are lucky and clearly have a good life, nobody can't deny this. But they don't make as much as it look, they aren't as many as some think, and they works way more than it looks.