10th percentile compensation for senior engineers in the US looks something like 350-400k/year. (At a rough guess, Amazon, Google, Facebook, and Apple employ 6-7% of the software engineers in the country, and there are enough other firms paying similar amounts of money that 10th percentile sounds about right.) This is with pretty great benefits, too.

I'm pretty happy with the trade-off w.r.t. freedom of association where a business can fire me for ~any reason at any moment, and likewise I can go and get a new job paying mind-bogglingly huge amounts of money with minimal friction. (No amount of "worker rights" will save you if the company employing you goes under, like so many did in the dot com era.)