I've been lucky to avoid the California cult of the 20-something my whole career. The infatuation with youth exaggerates the weird peaks and valleys of a tech career. Doing anything substantive in your 20s is a sign of brilliance, and you get a little too accustomed to the praise.
To some degree, those at the peak (or who want to appear to be) perpetuate a belief that 30 is retirement age in this industry -- despite all the statistics to the contrary. You're not necessarily better at what you do, but you're damn noisier when you're in your 20s.