The problem is that your calculations aren't just "grossly simplistic", they completely ignore the cash bonus, which again, is the entire problem. The cash bonus is a core part of the compensation strategy, which means you must include consideration of it in your calculations for them to be accurate, but you did not do so.

Even for the person who receives $150k in RSUs, they are still simply receiving a dollar amount. It doesn't matter if it's in AMZN stock or if it's in cash, because the cash amount and the AMZN stock can be exchanged equally, and B has just the same opportunity for stock growth as A has (because either of them can purchase whatever investments they want with the $150k they receive, regardless of it it's cash or a stock unit). If you aren't considering this, then all of your calculations about "which situation pays more" are wrong.

>The scenarios become endlessly complicated if we consider side investments in individual stocks.

And they become completely useless if we don't consider it. Attempting to simplify your calculations isn't a good reason to make them wholly inaccurate.

They also aren't "endlessly complicated". It's still very simple: any investment opportunity that A has, B also has, because they are receiving the same dollar amount of compensation that can be invested. So when comparing A vs B, there is no difference.

>So a large number of AWS employees may not be receiving 80% of their stocks.

Again, this doesn't matter, because they get cash instead of the stocks.

You are making the classic mistake that many make that imagines that RSUs are fundamentally any different than just receiving cash. But they aren't. Receiving an RSU for $3000 is the exact same thing as receiving $3000 cash and then using it to purchase $3000 worth of that stock. There is a reason that the IRS taxes RSUs vests just like normal cash income.