I find it hard to believe it’s the case for an average researcher, we know their pay package for most L6 engineers is a bit under 1m. But maybe a “fellow” or distinguished engineer?
But the most important point is, you don't get that money now, and maybe never. The most likely scenario where you get that kind of a payday is if they go public and if the pre-IPO pie-in-the-sky valuation holds for a good while.
It might. But it's far more of a gamble than your FAANG stock.