I'd personally bet money on it being a solo project from him (until he open sourced it). I never saw compelling evidence for the collective theory.
If you dig through all of his forum posts, emails, and code, it's entirely consistent with a solo dev reading a bunch of papers, combining ideas (digital currency + hashcash), iterating on some software, and interacting with his community.
You’re correct. I’m not really denying any evidence, just there remain a bunch of mysteries around Satoshi’s identity, that all we can do is say “it could be this OR it could be this OR this could have happened OR they could have been this”. One can “or” oneself all day long in the face of a mystery or a paradox.
If you dig through all of his forum posts, emails, and code, it's entirely consistent with a solo dev reading a bunch of papers, combining ideas (digital currency + hashcash), iterating on some software, and interacting with his community.