Ok, I’ll bite. In Czechia, $70k will get you pretty good web developers and you’ll easily overpay many companies with that salary.
As to the skill level, well, I’m trying to move from the web development because it is easy and boring (but pays the bills). Backend can be at least somewhat entertaining, but it still doesn’t hold a candle to stuff like network replication, physics simulation, rendering pipelines or embedded systems, OS development and so on…
At the end of the day, it’s a glorified button positioning. You use UE because implementing that on your own is almost impossible. You use Angular because everyone uses it, but implementing your own would take you like a week (been there, done that, with SSR, in js and php 
like ten years ago).
$500k for a webdev… dying here