From a technical challenge standpoint, trading is extremely difficult. But it provides high upside which only starting a business can exceed. However, starting a business has all the other uncertainty (regulatory, accounting, insurance, licensing, taxes, customers, branding, sales, product-market-fit), making it far more psychologically challenging overall. Startup founders need to learn and juggle a lot of things instead of hyper-fixating on markets. Basically, if you know you are sufficiently intelligent and talented as an engineer, your expected return is likely much higher in trading (especially via a big quant firm), with much lower risk.

If we want more talented traders to become founders building economic value (which we should all agree on), we need to make it less onerous to start a business.