Check out this blog entry by A VC. 10 of 11 portfolio companies have the leading entrepreneur 30 or under.
I heard someone the other day say "I must be getting older, because this new Office 2007 is hard to figure out." This guy is in his early 30's, and is tech-savvy. He reflected that "technology is getting harder to keep up with" - where a few years ago he might have said "technology innovation is exciting!"
Do our brains stop innovating past 35? Not only past your prime at most sports, but also innovation?
Or do we get tired of trying to keep up? Adding too much responsibility from other pressures (building a family, planning retirement, etc).