However, your example of fonts is definitely not one of those areas, anymore. Font rendering on Linux is as advanced and capable as any other OS including in the areas of kerning and hinting. It should just work without any user intervention and look great.
I agree with you that compositing/window manager fragmentation is a problem. And this article is a perfect example of that. The author may think that they're happy using i3 with Firefox and st at the moment, but the desktop computing environment has gotten so complex and the expectations of users who interact with desktop applications so rich, that a small hobby project DE/WM cannot fully satisfy all of those use cases over the long term. The only two desktop environment projects that have enough resources to meet the needs of users behind them are KDE and GNOME. And we shouldn't be telling new Linux users to try anything but those two.
FWIW, I've worked at Google for 7 years where we use Linux on our workstations. Many engineers fiddle with various "hacker" window managers like i3, Sway, Awesome, or fvwm. They almost universally give up and switch to GNOME(/Cinnamon) or KDE: it's just too fiddly/not complete and they'd rather use their brain power for solving real problems. The authors example of messing around with dmenu because "unix philosophy" is an example of this kind of waste of time that people eventually get tired of because they have better things to spend their time on.