That’s definitely one of those easier said than done things, that someone who’s never tried to do will think.
Publishers have benefits, there’s a reason some game, developers, and other type of media creators will eagerly sign away a big chunk of their revenue. Not true for every media or genre, but there’s a reason these companies exist.
most publishers dont give money without seeing a fairly elaborate demo. And making games is something that can be done with zero budget unlike endeavors in many other industries.
Outer Wilds was in production for 7 years. Practically nobody can fund years of full time work without some external funding. I don't have any proof, but I am confident that Annapurna poured some amount of money into that venture during those 7 years.
IIRC Mobius Digital got their initial money for Outer Wilds from crowdfunding after a much more limited demo of what they wanted to achieve, then I assume Annapurna came on the scene later when they went professional and needed support for multi-platform. The period where kickstarter was more commonly accepted for game projects is over, and fewer projects could get a similar starting point that lets them spend years on their first release
