"But as the company grew he had to deal with more of the business side of the things. He still set the broad outline of priorities. But he gave me mostly free reign of determining how and I would just give him a brief high level of overview of my decisions. He did what a CTO was supposed to to do - grew the capabilities of his team."

That is a good summary of the progression of a successful CTO. The capabilities of the team is a summation operations, not a selection operation.