Yeah - most Holoindies are made by prior devs. On the talent front, though - I did see Machina X Flayon work on his own RPGMaker backstory game, though- and I know Houshou Marine had similar experience with a highschool project she had.
I think one YouTuber who does game development/behind the scenes bugs videos that I really like is Skawo. He usually does playthroughs of Nintendo games, but when he does a behind-the-scenes deep dive, his videos are well-presented and well-edited. Might be worth looking through his stuff - or anyone else who's worked with The Cutting Room Floor!
Yeah, I'd love an organization that would connect people from different fields... The US has some, but it's not quite on the level of people making doujin circles in Japan LOL.