I think these are all really good points, but I was sad to see it didn't address one of the largest reasons my side-business is going to stay side-business until I find someone I can envision really starting with -- you need someone to lift you up.

I sit in the school of thought that says you need a co-founder to disagree with you with a passion you won't find idly perusing Reddit, but you raise a few good points. One thing you don't address is the overwhelming feelings of "I can't do this" or "I shouldn't do this". Those are the points where you need someone you trust to be on your team, because it's likely these moments of despair won't sync between the two of you.