"The wealthy people" got wealthy in a whole bunch of different ways that are not investment; and having gained wealth, they invest it for many different reasons aside from maximizing log-mean expectation (or probability of sustaining a given level of cash flow, or other objective metrics that only consider the investment itself). Hiring a well-compensated "hedge" fund manager (many of these funds are not at all about hedging) is barely any more "effort" than buying and holding SPY, as the work is being entirely delegated. Many strategies are dependent on that level of wealth (or designed to address problems that only apply to that level of wealth) for tax-related reasons.

There is plenty of evidence that most lay people who try to time the market lose out on average, and I see no reason to expect you to be an exception. Active trading loses out on average to indexes by mathematical necessity, as both grow on average proportional to the total value of equities, but active traders (and holders of actively managed funds) are exposed to higher fees. The only winners there are the market makers.