Something like this seems inevitable for distros that have been based on Ubuntu, as Canonical seems increasingly set to make Ubuntu into "Linux for Canonical customers" instead of the old "Linux for all humans".

Vanilla OS is also switching from Ubuntu to Debian for similar reasons – closer to a vanilla experience and not having to spend time detangling snaps

Interesting thread overall. Maybe I'd contribute my two cents

Some considerations:

• Linux Mint may make their debian-based as their main thing
• CalVer might be better for a more general audience, according to LibreOffice project; SemVer, on the other hand, seems to work well, as shown with Fedora project
• Ubuntu's release cycle is very predictable, with their release every month 4 and month 10, LTS on every month 4 of even year; Debian's isn't as neat and predictable, but for the last couple decaded they've been making release every two years rather consistently, albeit the irregular months
• Ubuntu may have the edge with their more up-to-date software for the regular release, but people may not care that much especially now we have Flatpak as the equalizer; as for the system package, Debian now has all the non-free drivers for nvidia and all their nonsense, along with the backport repo to enable if one really wants the more up-to-date software

Would they rebase to Debian? At the moment we cannot tell. We can assume they'd stay with Ubuntu as a default, but we have nothing denying it can be otherwise.

Would it be a huge undertaking? Most definitely. But we've seen System76 taking a bigger undertaking. Indeed rebasing system packages would be nothing compared to creating DE & system mainboard from scratch.

It also helps that both Debian & Ubuntu use the same packaging system and follow the same package naming convention for most packages. This would cut down a lot of the time required for initial design & implementation, leaving them with testing & bugfix as their major parts.

It would make sense to start by having it as alternative just like LMDE.

Would they rebase to Fedora? I don't think it would make as much sense, but we've seen something like this done. Still, I think they might as well create a whole new distro (or edition, since it would make sense to keep this name with a lot of publicity attached) if they're to go this route.

That's a large undertaking. Maybe when they finish with Cosmic they might switch but that's years down the line.

I think Ubuntu is a for-profit company. I think System76 is a for-profit company. As a rule, companies tend to respect other companies in ways they don't respect people.

I think it's more likely that System76 will rebase to Debian than Ubuntu kick them off, but if Ubuntu really starts pulling out the brass tacks, I don't think System76 will show any loyalty.

In other words, I think Ubuntu benefits from counting all the Pop!_OS users as part of the Ubuntu family (at least statistics wise), that they'd be killing a golden goose by trying to evict them, even though they'd obviously prefer them to use Snaps.

So something I just thought of, and I'm surprised nobody brought up (well, I guess some did indirectly, it just wasn't obvious to me): A major benefit of basing off of Ubuntu is more up-to-date hardware support. While it's true that Debian now supports non-free firmware by default, that doesn't mean that it will be recent.

Debian support for hardware is truly impressive, but it ultimately lags behind because Debian prioritizes stability over new features. This is why routine Debian updates only cover severe bugs and security issues, and from what I can tell that also is the case for hardware support and the kernel.

Ubuntu tries to keep in step with new hardware releases, which makes much more sense for power users like engineers, developers and gamers, all of which seem to be key consumers of System76 hardware. Basing off of Ubuntu makes it easier to satisfy that clientele. I imagine it also makes submitting upstream fixes for hardware-related packages easier.

The advantage of being Ubuntu-based is faster updates.

The drawback is Snap, but it can be disabled.

Therefore, I think Pop and Mint should continue being so and doing that.

On a side note :

CalVer might be better for a more general audience

I disagree with this nevertheless, because when users learn what major/minor/patch mean, they can better understand how developers work and why should they upgrade.

Also, coincidentally but relevantly, CalVer is an homonym of the French calvaire which means misery.

I can't make any predictions, but I might see a few problems with moving to debian. Flatpaks are a pretty good replacement for lots of apps, but especially with stuff like drivers for Nvidia cards (and supporting Nvidia so well is something Pop!_OS seems to like), you just can't get all the way with the debian repos.

I think if they were to move, imo it would be more realistic to use something like Fedora as a base.

Probably not. Ubuntu has predictable release schedules which helps when you’re a business.