Comment by yissp

It could also just be that people generally have fewer responsibilities and probably a higher risk tolerance earlier in life. Once you get into your thirties you might have a family, be more established in a given career path, be thinking more seriously about saving for retirement, etc. For all of the big inventions or successful companies you're thinking of, there are likely many more that turned out to be failures, and that's less of a setback to someone in their twenties.