No pun intended:

Well fuck.

You're right, they literally did just do this, almost tagged everything NSFW/Adult no longer appears in itch.io's search, I just made a new account and specifically checked the 'show nsfw stuff' setting and.... yep.

Currently I am only seeing like uh... 3 games.

There used to be 100s, probably more like 1000s.

They have not taken down the actual urls for actual games, but you have to know them directly.

Kotaku seems to have an actually decent overview, very recent:

https://kotaku.com/itch-io-nsfw-porn-games-delisted-collective-shout-1851786841

Well uh... if itch actually sticks with this decision... either as you say, somebody is gonna have to figure out how to run a crypto based adult game platform of similar scale to itch, which will not be easy for all the reasons I've described, or create their own nsfw-friendly payment processor system, which would also not be easy.

So, that means that largely donation based nsfw game development is now effectively over, at a stand still, untill someone figures out how to at least semi-automate some kind of workaround via probably some kind of much, much sketchier 'sending money to a friend' type loophole in venmo/cashapp/chime, etc, which is also probably very legally dubious/iffy at a platform level.

The whole problem with all this (aside from the business/platform end costs and complexities) is that even if you do switch over to crypto, or make your own payment processor, or use some kind of loophole, its now much more difficult for an average person to go through all these steps.

I guess this is the -current year- version of back in the 90s and early 00s, the FCC and RIAA cracking down on 'explicit' music, the younger generations will now have to get clever and do something analagous to invented torrents, but that actually results in money moving around to support devs.

EDIT:

A quick search shows that there are indeed alternative, minor payment processors oriented toward or friendly to things like strip clubs / sex toy shops, who transact in USD.

https://www.merchantmaverick.com/adult-payment-processing-merchant-account/

Probably the most straightforward business solution for an adult game platform would be to use one of these, but uh, they'd likely have to make a whole new brand name, a new website/domain, a different company legally, to avoid what PayPal would otherwise possibly see as you violating their policies.

Again, you could use crypto, and wow hey, finally an actual compelling use case for it!, but uh, either route you go is gonna be complex and risky for platforms, creators, and users/consumers... tradeoffs.