There is nothing inherent about having a bad window manager that makes it more power efficient; Apple could implement a better desktop environment and still have low power use.
You could also install a window manager such as rectangle or magnet if window management is a big deal for you. People switching OSs expect some things to roll over and then forget that they can google for potential solutions when things don’t work the way they expect/want.
I, like the author of this essay, was prevented from doing such things by my employer when I used a Mac for work.
I do also want to point out that such suggestions - "just install and configure [some software] which will solve your problem" - are generally rejected when I point them out to people who are having a hard time getting started with free desktops. The KDE or GNOME environment are expected to be perfect at installation, but Windows and Mac OS are afforded more leniency. It's a double standard.
