There are plenty of highly talwnted people who work for existing companies vs start their own thing. The fact that big companies often acquire startups I think has less to do with caliber of talent and more the focus of that energy. You are asked to move some KPI OKR whatever. And you are evaluated on how much you move it on at least an annual basis. Successful startups often take many years to become valuable or product revenue. It's too risky for most companies to hold off evaluating for that long.