I get calls weekly from people seeking technical co-founders. The biggest thing most CTO candidates dont realize is the power they have -- unless the "business co-founder" is actually bringing something to the table.
I'd LOVE to work with a "Business co-founder" who actually brings Purchase Orders, Funding, Transact-able Relationships, prior wins (esp publicly verifiable wins). That would be a dream.
It makes no sense to work with a "Business co-founder" who wants ME to put in hundreds of hours of technical work -- upfront -- often for equity "e.g., free" -- and retains the right to take all the upside and has none of the downside. Why would I need a "Business Co-Founder" at all in that case, I might as well be the only founder and recruit later.
I see tons of friends burnt by these types of "deals." The biggest red-flag is when the "Business co-founder" still has a job and no real skin in the game.