I'm supposed to work on the code my boss is paying me to work on, not tinkering with some OSS project to get it just the way I like it. Basically, my OS needs to be able to launch an IDE, a shell and not bother me with irrelevant shit ('Windows just found an USB mouse...').
Setting up something complex definitely takes time and has its cons but that time is definitely finite, I am not saying that I magically got to my setup, it did not take me a year either. And once it is yours, it is yours. Moreover, when the environment is easily extensible like Emacs and StumpWM are it is easy to mold them to a new task that lands on your table.
This is one of the nice things about macOS, every update is just a small refinement of the previous years OS. Most of the time when you update to a new major release you have to go looking for things that changed. Sure there may be new features but many of them you only notice when you dive deeper into some of the functionality. The basic desktop is still the same.