You assume that super successful people don't read Hacker News? That's an interesting thought, but doesn't hold up to scrutiny. What he said is likely true. Furthermore, I'm not sure why the stock market should necessarily be tied to U.S. GDP save for the outsized influence that U.S. has on the world economy as a whole. A company like Apple, for example, sells products all around the world. Their market cap is pretty detached from the U.S. GDP.