Your team appears to lack diversity with regards to age, and your conclusion makes it sound like that was almost a goal. Older engineers can offer a lot of wisdom and save a lot of wasted effort
How many highly experienced individuals are going to join a seed stage startup as a regular employee?
It's founder or no deal with early startups for most people I know above 40. You join as regular employee - maybe get 1-3% at the high end. Founder? Order of magnitude more.