Does that mean the Founders Fund wasn't interested?
Is it common for a VC (especially a prominent one) to invest their personal money into startups, as oppose to their fund's money?
This might help: http://www.danshapiro.com/blog/2010/08/vc-insanity-economics...
The whole point of investing like this is that a home-run can offset a large number of failures / also rans.
The Wright brothers have a horrible record of making things fly if you removed the flights made at Kitty Hawk.
He is connected, famous and rich so he can afford to and can pick the early stage companies to through a bit of money at, hoping a few strike. But, there's a difference between billion dollar sized funds and angel ones.