Sorry I may have come across as bashing; this was not my intent. I have nothing against FE work, as I do both myself. I work in a small two-man shop and I have to do a little of everything, including sysadmin stuff, which I don't really like, but it keeps me up to date.
Editing to add, no, I don't work with React. I primarily live in Python, Bash, and PowerShell in a mixed Linux/Windows environment. Starting to do more with IoT for sensors, etc. and this is where things like Python shine.
It's interesting how you have such strong opinions about JS developers when you're not even familiar with the most popular tools that are available today... I always find it weird how people are like that.
Especially mentioning JS and then saying immutability is a problem... Immutability is a core concept in React, so you couldn't be more wrong honestly.
I'm curious, have you used React or Immutable.js? As the latter's name suggests, both heavily rely on concepts of immutability.
Just sounds like you're FE-bashing like people on the internet love to do.