Yeah, you're right, that's a reasonably good approach to developing games from a professional perspective, but once again we'd have 10% of the games we have in the best case scenario.Oh, there are alternatives, which worked for others (I also helped finance adult games, just not with a subscription model).
Learn to render in spare time while actually going to work. Write the story in advance, so you have an idea how big the whole thing will be. Once you feel fit to start a project, make an estimate how much work is needed for it, how long it will take, how many renders are needed. Break it down into smaller parts if necessary, but plan for the whole thing, not just for one Chapter. Do a calculation how much that will cost you. Triple that (at least). Create a prototype and see if you can get the funds to create the product.
If the whole thing is too big to be planned ahead, then ok: Do one chapter at a time and charge for each chapter once, do the calculation for that one chapter and see if you can raide the funds for it. This way you have more motivation to actually finish your work and will try to stick to the plan, not put in 500 ideas which came along the way. This way you will learn to postpone ideas, maybe implement them in a later update.
Will this lead to less games? You bet it will. But it will also lead to games created on a higher level. What good is it to have 200 mediocre games half finished and then abandoned if you can have 50 games from people who actually know what they are doing.
If one wants to "learn by doing", he can create smaller games to experiment with or a demo for the project he wants to create, with a goal he wants to reach, thereby not having big costs and getting an idea if he actually is able to reach a goal he set for himself. Don't make others pay for your learning phase.
On the other hand, this would probably get worse because a try and error development paradigm opens the door to test new things, lets your creativity fly and in many cases, as a result, a good game is born although it didn't look so promising at the beginning thx to the supporters who saw its potential.
So all combined, your proposal is perfect on the paper and works fine for certain games but in general doing it this way would mean a change for the worse in terms of global results.
With patreon and other similar sites, you can always support little money per developer (1$ per month, for example), which means 12 * 10 = 120$ for a 10-year game (I guess this could be a reasonable development time). Are you ok with paying this money for a game? Besides, you're not forced to support a developer forever. Personally I've stopped supporting some developers once I've noticed they were too lazy, I don't see a problem with that.
What if everybody did as you do? And related to this, what if pirate sites like this one didn't exist and we were forced to pay for everything? I guess you know the answer.
Regards