I have always assumed that when we hear about $1M, $500k "junior", etc devs they're including stock based comp. While I am just an IC so obviously not near the upper echelons, I've never been aware of base salaries for ICs being in those regions.
I think the 500k TC posts are usually talking about the massive stock appreciation that the FAANGs have gone through.
For example on Feb 4, 2019 Amazon was trading at 1623. By Feb 4, 2022 stock is trading at 3,112. This multiplies the value of any TC in years 3 and 4 by a significant sum (given the 5/15/40/40 vest) due to the near doubling of stock value over 3 years.
It's normally inclusive of stock comp, although some companies like Netflix let employees choose to get most or all of their total comp in cash if they want to.