Why interviews are failing at large and small companies?

Brian Acton, founder of WhatsApp, which was acquired by Facebook for $16B (B really B), stated in tweeter that he was rejected by Facebook in 2009!

So, you don’t hire someone for $1X0K range, then you buy him for $16B? 160,000 times more! Of course Acton would not be as valuable as an engineers, as he is as a successful entrepreneur, but my point is: If this isn’t a sign that interview processes are a failure – even at Facebook – then what is it?