I mean depending on where they live and after Patreon's cut that's a fairly standard wage. They do massive updates very intermittently.
They have already stated they would much rather do it this way and give us deep quality content than just push out a small update every few months like other devs and only provide us a miniscule amount of content.
Something like Freshwoman is making A Lot more money actually being on Steam, here and Patreon and they only provide maybe an hour of new content every 4-5 months.
This update completely reworked the entire game and doubled the content. I'd say that's pretty good.
Ripples took off half a year just to rework the first couple of chapters.