Of course, most Americans don't have Ma's net worth of $3.4 billion (nor do several countries). So most Americans don't have the luxury of retiring as soon as they feel their thoughts lose their freshness. Over half of adults 50 to 64 say that they may delay their retirement, according to a 2009 Pew Research Center poll, and another 16 percent said that they expect to be working until the end of their days. A Wells Fargo study found that 30 percent of middle class Americans said 80 was the new retirement age.

But Silicon Valley isn't like most of America. While younger minds might be more adaptable to the tech world's rapid flux, many in the industry also straight-out discriminate against older workers, preferring the sneaker-wearing wunderkind. It's "100 percent due to the new, young, tech startup mindset," one San Francisco employment attorney told Reuters, noting that he has received many calls from folks who feel like they're the victim of age discrimination -- who are in their early 40s.

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