Earlier quoted context omitted.
"that can get them retired easily by their mid 30s" Maybe a small subset. The median dev salary is $110k. So no, only a very small number are able to retire in their 30s.
The absolute value of your salary doesn't tell you anything about how long it takes to get to retirement (or more accurately, financial independence). That's exclusively a function of your spending and saving rates. https://www.mrmoneymustache.com/2012/01/13/the-shockingly-si...
This is very unlikely long term. Right now treasuries are 5% less then inflation. Lots of FIRE people are going to get shafted.