Hardware companies trying to write software usually ends in disaster. (Yes Lenovo, I'm looking at you)
Since Pop_Os is derived from Ubuntu, you could argue that this is just what they did.
I'll bet upstream is more-or-less welcoming of an additional (well funded?) stakeholder. The bug reports alone might be worth the effort, especially if System76 is triaging some.
The number of FOSS contributers is not infitine. At some point we need to start working together instead of forking yet another marginally different copy.
I understand some diversity is good, but what popos adds could have been added to vanilla Ubuntu (or Debian, if you feel that way) and benefitted many more.
To address your original point, I suspect it's more expensive and slower (at least, in the short term) to add features to someone else's distro than to fork it and keep building it out yourself.
Nothing. Everything we create here at System76 is open source, either GPL or some form of permissive license.
(Edit: To be clear, I'm just answering your rhetorical question, not insinuating anything about the tone of your post for sure.)
I just figure Canonical probably has a specific vision for Ubuntu (just like System76 surely has for Pop!_OS), so they don't necessarily want to pull in every feature from every downstream distro. The prevalence of purposed-focused distros is one of my favorite things about the Linux ecosystem.
I actually haven't used Pop!_OS yet, but it looks good and it's on my short list of distros to try. I didn't mean to imply anything negative about it.
(/s)
Of course, maybe there is a demographic that is in to this sort of branding, but I bet it's more of a detriment to overall sales than anything.
Is the OS as full of seconds-long bouncy animations and bubble letter finds as the branding and website makes it look? If so, can animations be reduced or disabled?
(Even Fedora or CentOS are not nearly as comfortable to use in my experience, although they might be preferable in other ways!)
I built one with PoPOS (however you spell it) about 6-8 months ago and absolutely love it. I've previously used Xubuntu, Linux Mint, and Fedora and PoP!OS had a lot of the things everyone installed already taken care of and the UI is useful, but minimalistic.
I don't personally use it, but I've heard of people actually using it on other hardware just because the system is supposedly so polished. And maybe because it has better support for proprietary firmware? I forget.