(I agree with your general idea and the rest of your comment.)
https://www.superlectures.com/guadec2013/sandboxed-applicati...
Unity came about with the Gnome 2 to 3 transition (and earlier versions of Gnome 3 were widely agreed to be a step backwards).
Upstart has a very different design philosophy than systemd. Hard to say its NIH when it was different tech.
NIH apparently means "not adopting whatever RedHat develops/supports".
Flatpak was known about and talked about before snaps, as another pointed out.
Upstart - that's fair, upstart was something new that didn't get replaced by systemd for a couple cycles.
Like it or not, Red Hat controls gnome which is a huge ecosystem. Your best bet for effecting change there is collaboration, not hacking together your own UI for yourself. I mean, sure they are free to do that, but the writing was on the wall before it even started.
We should encourage experimentation and risk taking. No company can always get things right.
Phones are a duopoly, but I'm glad they tried. Unity was fairly decent, but in the end adopting Gnome benefitted everyone. Ads were the only bad idea I can think of; but hey I've been using their wonderful software for 15 years now at a total cost of zero.