It's because these "donations" are required for the livelihood of the developers of the project. Those other non-"AVN" projects have an idea of how much they may need and they try to hit that goal, and then they do their thing. Lots more people buy into them than these "AVN"'s because these "AVN"'s are quite niche.I absolutely get what you're saying, however.
At this point, the AVN economy has gotten funny. No other game or a Patreon project has this kind of economy.
For video games, you pay $60 once and you get the game forever. For lewd Pateon pics, you get a new batch every month you pay. But for AVNs, you can pay as much as $60 per month to explicitly not get anything but a dev diary with excuses about why they did nothing in the last 2 weeks (not talking about you, obviously, just in general).
Now, I get it that EVENTUALLY, there is a free release. But you do realise that a whole two weeks of early access is playing into FOMO-ness of it, you admit as much. Video games have become savvy to it as well, with all the "advanced access" shit they're pulling for more money.
I genuinely hate these dark patterns made for making money out of people with weak impulse control, and on top of that, no AVN is worth $50 per update.
If it was about $15-20, I'd think about it as a gesture of goodwill, but $50 is just funny.
It'd be impossible to sustain these projects without continuous donations, the dev. won't be able to make a living, but I do agree that they're absolutely not worth that much money, but some people are willing to pay it. It is what it is.