Minor nitpick, but thanks to payment processor and other fees that are applied on top of the Patreon platform fee, most AVN devs probably have closer to 15-20% of their gross revenue taken by Patreon before taxes. Small payments tend to get hit hard by payment processor fees in particular, which makes up the bulk of subs for most devs. That's also why you might occasionally see signs at gas stations and convenience stores that say something like "Credit Card $4 minimum" or similar. A $1 payment easily could have 30% or more taken for payment processing fees alone, depending on the terms. If you're curious about the likely Patreon terms, you can find their Patreon creator fees overview page pretty easily via search.
It's honestly a bit frustrating as a supporter. Technically the devs I like to support would get more money if I paid them $12 once per year rather than $1 per month, but cycling that would be a pain and I'd miss their dev updates and previews. And I definitely can't afford to support a bunch of devs at $10+ monthly payments year-round.
EDIT: Just wanted to add, that if you sign up to support a Patreon via the iOS app using Apple payment method, they now take a massive 30% cut before it even gets to Patreon, who then takes their platform fee on top of that. So yeah, sign up via web browser or something if you use an iOS device.