I had the same experience with dwm, and this is the reason I keep using it.
I spent a day to set my system up a couple of years ago, and never had to touch it again. There are no dependencies, so it does not break on updates. It has so few moving parts that nothing ever goes wrong. It gets out of my way so that I can get the job done.
Moreover, I can sleep sound, not worrying about how they'll replace the toolbar with a start screen in dwm 8.0, only to change it back in dwm 8.1 after I spent the better part of the year relearning my workflow instead of doing my job.
Aha, so in some sense the software was still not totally suckless to you.
The "I don't want to spend time configuring my desktop environment" argument misses the point with these things. Everyone had to learn how to use various interfaces. It's easiest for me to learn something whose code I can mess around with
I don't like dealing with multiple things on my screen (from the WM, tmux panes, Vim windows, whatnot) and like focusing on one thing, so I've had a pretty simple and straightforward "full screen all the things" workflow for years (well before I used dwm) which doesn't demand much from my WM. I mostly use tags/workspaces, tmux windows, and Vim tabs to switch between things.
Unless that was the first time you used those tools, how long prior to that did you spend getting to a state where you could do that?
I don't think suckless is for everyone; it's pretty explicit about that. I think that's okay: not all software needs to cater to all users; suckless is mostly a hobby project by some devs for their own purposes.
I sometimes see people recommend dwm or st in "what {WM,terminal} should I use?" and I think it's a terrible recommendation, because most of the time people asking those questions don't have the required skill set to be able to use it effectively (not yet, anyway).
I set up dwm, st, and dmenu once years ago, and have worked flawlessly without faults ever since. I actually use a stripped-down hacked-up dwm that I did on a Sunday years ago and have since lost the source for it; I can't recompile it even if I wanted, heh (which is not ideal, but I have little reason to spend effort on it).
> Would the tiny incremental gain from tweaking one or two specific settings to my perfect liking save me anywhere near the amount of time, happiness, or productivity that I save from just letting someone else choose the defaults for me?
But that's not without overhead either. If you update your Fedora or Windows you'll sometimes need to spend time getting used to new defaults and the like, especially on the long term (e.g. Windows 7 -> 8 -> 10, or if you use Ubuntu, Gnome -> Unity -> back to Gnome). With dwm, my experience has remained unchanged for a very long time.
I can only speak for myself, but your description of a hacker constantly fiddling and compiling their software couldn't be further from what I'm actually doing with suckless/dwm. Funny enough, I like it for much of the same reasons as you like Fedora/Windows: it gets out of my way so I can spend time on more important stuff.