If you invest in the sp500, you'll have something around 8% return per year. This is highly variable year by year, of course, but in the long run, that's what you can expect to average out. You can do better than the sp500, but generally not without accepting higher risk.

With those returns, you will double your money every 9 years. Roughly. It's going to vary by decade. 2000-2010 was flat, while 2010-2020 was unusually good.

If you max out a 401k, HSA, and IRA on this strategy from a young age, you should have millions for retirement. If you're a millennial or younger, you're going to need a million or two (at least) to have a reasonable retirement.

How do you turn that into a billion? Doubling every 9 years won't do it in your lifetime. Not unless you started life as a millionaire and never withdrew a dime until you were 90. Starting with $1000 and doubling every year for 20 years, consistently, would do it.

How do you double your money consistently for 20 years? Either extreme luck or doing something extremely shady. Probably both.

In other words, they are not the genius captains of industry that right-libertarians want you to believe. They got lucky or are deeply unethical or both, and they do not deserve your respect. Most likely, they deserve your disdain. Every one of them.