That's incredibly reductionist and misleading.

Most people become rich by being good at a job or skill that makes them essential, either easy to be hired or hard to get fired. After that, the majority of people gain weath over time until they erase all non essential debt (house or insurance payments), and then have enough on hand savings in order to diversify their income sources.

In other words, although the majority of stockholders don't actually possess the skills to run a company they have invested in, they didn't just get born with a $1,000,000 in Microsoft. They invested after they became financially self supporting.

A very few (less than 10%) actually have generational wealth. The majority of others (I believe it's around 70-80% though i can't remember the actial number) get rich by working steadily and paying off their debts.