Travis Kalanick — Uber

Kalanick dropped out of UCLA to pursue his first startup (Scour, a peer-to-peer search engine that got sued for $250 billion). Undeterred, he co-founded Uber in 2009, which peaked at a $120 billion valuation and fundamentally changed urban transportation worldwide. He was ousted as CEO in 2017 amid culture controversies but cashed out roughly $2.7 billion in stock sales. The man who couldn't finish college built a company that killed the taxi industry, invented the gig economy, and became a verb. "Uber" is literally in the dictionary now.