What whole team? Most of the new content is by volunteers, which they'll paywall for a while and barely do anything themselves. Even the bugfixes are often coded by a volunteer, it's honestly just milking it and has been since towards the end of the first Corruption of Champions. People will write the game for Fen & Co so they don't bother that hard, except maybe commissioning some art but even some of that was free fanart they made "official".
While a large portion of the content, especially written stuff, is volunteer, I think you're underestimating how hard some of the other stuff can be since they're not using a per-structured engine like RPGM or Renpy, and both of those still require some effort to get non-generic results.
And maybe I'm mistaken, but last I checked, it's no longer one dude building the game as a hobby in his free time, that's my point. With the amount of funding they've raised and I believe at least a dedicated coder now, they should be able to slap stuff together and advance rather quickly.
But hey, I say that about a lot of other projects too. There are games on here who have made many times more the funding of massive hits like Hollow Knight and have either the same-sized or larger teams and have been in development
longer that will never amount to anywhere near even 1/100th the quality of those games and are STILL not even close to done.
It's even worse when you mostly use generic components of engines like RPGM, it really shouldn't take you six years to slap in artwork you more than have the money for while doing the writing.
For a game like TiTS, it really should be blazing at light speed. Degrees of Lewditity is still basically one guy but also with help from volunteers and some of their per patch inclusions trump what TiTS and CoC2 have managed in years, lol.
I do agree with you that it's mostly milking now, but I mean, I'd say that about 99% of western developers on this site... everytime a new project (with a patreon, of course) is announced all I do is sigh and roll my eyes mostly. Asian ero devs got western ones beat by spades and miles.
Maybe I'll spend $50 to commission some lazy ero artwork, slap something together in RPGM, and then collect my paycheck every year for free too. Why not.