By my logic, to make bank from a startup, you need to be a master negotiator constantly watching your back, parsing poker faces in meetings, reading fine print in agreements, and trying to bust other people's schemes, while scheming on your own. You won't have any time left for the technical side.

A CTO, in theory, is supposed to be shielded from all the political screwery, and focus on delivering the product. In practice, it makes the CTO's equity one of the easiest targets for those willing to play games.

So, unless the CEO/CTO relationship is decades long and is worth to both sides more than a short-term gain, CTO gets screwed.