I'm 44 and worked at various bay area startups you never heard of from 1998 to 2005, at which time I moved out of that area.
I don't have precise numbers, but based on a cursory scan of my linked-in connections, some of my cohort has followed that path and moved out. Another big subgroup is the people who went to google or some other Big N. In particular a lot of the high performance people did this.
Another person who replied to you suggested that CS/programming is just a lot more popular now and I think that is big part of the reason why it skews young. When I graduated (in 1997), CS was not a popular study. As a consequence, startups back then had a wide age range (20-60+), but still were quite youthful overall.
I don't have precise numbers, but based on a cursory scan of my linked-in connections, some of my cohort has followed that path and moved out. Another big subgroup is the people who went to google or some other Big N. In particular a lot of the high performance people did this.
Another person who replied to you suggested that CS/programming is just a lot more popular now and I think that is big part of the reason why it skews young. When I graduated (in 1997), CS was not a popular study. As a consequence, startups back then had a wide age range (20-60+), but still were quite youthful overall.