> I suspect trading offers a higher expected value of return than starting a bootstrapped company. Startups, especially those not started by someone wealthy, have a higher failure rate than day traders

This seems highly unlikely

Sure, there are people that have the skillset and capital to earn a living from day trading that don't have the skillset or interest in running a business who'll be better off trading. But successful businesses selling products or services can consistently earn very large multiples of their initial investment, and day traders can't. Short term financial bets are much closer to a zero sum game than starting businesses. And we've already established that 90% of day traders fail, just like startup businesses. More than 90% since the criteria in this study is beat the index, not earn a living.