Fedora has earlyoom enabled by default but so far it hasn't saved me. I really need to look into configuring it. How did you get started? Man pages? Blog post?
If the results you're getting aren't expected, there's still some chance it's a bug somewhere, so you should report it against systemd, attach `journalctl -b -o short-monotonic --no-hostname` or at least ~10 minutes of logging prior to the unexpected behavior you're reporting.
-r 30 -m 5 -s 80
I run with 16gb of memory and do use swap. In practice if swap is growing at all once memory is near full, I'm in trouble and action needs to be taken.
Note that if enabled you can use SysRq keys to invoke OOM killer manually.
Given the letter they picked it seems like they're fully aware of the deficiency. As to why it was never really addressed, that's a good question. The recent le9[1] patch addresses the most annoying symptom of running out of memory by keeping some amount of RAM reserved for clean pages (like static program code) so that those won't get swapped in and out so much. That greatly improves responsiveness under low memory conditions.