From my perspective as a senior professional, the small number of seniors in startup management teams is very striking.
Senior talent complements that of the younger generations, it does not compete with it. Seniors conjugate well verbs such as plan, prioritize and collaborate, which are instrumental to optimize the hypothesis-test-learn cycle of innovative high-growth initiatives.
However, the perception that senior people have a limited ability to adapt to "dynamic environments" may be unfairly holding back their involvement in entrepreneurial projects. I think that there are few more flexible and dynamic exercises than the evaluation by a senior manager of different strategic or operational courses of action based on his/her experience and know-how.
Greater generational diversity in startup management teams would multiply their economic and social impact, while enabling natural and attractive opportunities for senior professionals. The reference of forward-thinking entrepreneurs and investors will accelerate this change.