So, I read the question slightly differently - and I would say there is definitely something here. I can imagine a consulting service (problem-solving and execution discipline for startups - kinda like what mckinsey does for the fortune 500 :)) that could bring structured problem solving, fact-based de-biasing (countering delusions of optimism), focussed execution, research, 'talking to users' (the famous YC mantra) and (I don't have good name for it) lets call it "learning from experience and experiments of others" etc may be possible as a service.
Its the help a startup needs between "office hours" and execution. I do think that there is a piece missing here, that can be developed.