It's true that they make a lot of money, so do the owner of a SME or a director in a large organization. It's not a position most employees will ever attain in their lifetime.
Directors are equivalent to staff +1 or staff +2. Staff engineers are usually equivalent to 2nd level middle managers, with 1st level are managers of teams that are just ICs). Jr Engineers can be 30-50% of an engineering organization. So it's not that impossible.
Director (L8) is two levels above staff engineer (L6) in Google. But promotions get exponentially more difficult after L5, particularly if you intend to stay as an IC.
We aren't talking about stock options, we are talking about concrete RSUs with real valuations.
A Staff Engineer at Google can easily be vesting $200k in stocks alone each year.