Silicon Valley's dirty secret - age bias
My first thought: narcissism. Narcissists hate being around older people because it reminds them that, some day, they'll be old and unable to do the sorts of things that narcissists tend to do on the weekend. I don't think that all founders are narcissists, but if you want to be able to hire narcissists (which 75% of execs are, let's be honest) then ageism becomes practical, sadly.Then again, I think some of it is subconscious and unintentional: unreasonably harsh age-grading, coming from an inexperienced and privileged set of people who've never had to do grunt work and therefore have slack-free careers. People who are young and have high career efficiency ratios expect a linear trend-- consistently improving projects-- but the reality for most people (save privileged 22-year-olds) is that they have to take the work they get, rather than being able to focus on their passion or highly-visible (e.g. open source) work. I, personally, would love to hire someone in his 60s with no slack in his career-- I'd make him my personal mentor and figure out how he did it-- but it's quite rare to find such a person.The reason ageism exists is that most people have to take low-quality, career-toxic work to (a) avoid income volatility that becomes more unacceptable with age, (b) evade the "job hopper" stigma, and (c) remain employable without moving to another city every 3 years, and this creates a world in which premature decline is far more common than it should be.