Billionaires over the age of 50 are placing bets on biotech startups. CHRISTOPHE ARCHAMBAULT/AFP/Getty Images What do Jeff Bezos, Michael Bloomberg, Bill Gates and the great-nephew of Walt Disney have in common? A pursuit to live longer, according to their recent spending pattern. A number of the world’s best known billionaires have been putting their personal wealth into biotech startups that work to discover the elixir of life, noticed Family Capital, a British publication that tracks the movement of family businesses globally.