Linux

It's predominantly a thing because System76 wants full control over the software that they ship on their systems.

Something I understand completely tbh - it's risky having the success of your business being dependent on another entity's software. Probably even moreso when Gnome is pretty notorious for having a desktop workflow that's very different to what you'd traditionally see, and that's controversial, potentially even alienating to some customers. So I'd probably want that control too.

When they used Gnome, they had to compromise, and in many cases, neither of them wanted to.

Over time, things became hostile between them. And to be honest, System76 were the more hostile of the two, IMO.

One of the more bizarre things to happen was System76 identifying and resolving bugs, applying them in PopOS, choosing not to upstream them to Gnome (twattish, IMO, but that's their right), but where it really crossed a line IMO was System76 staff going onto bugtrackers and forum threads, advertising that XYZ was fixed in PopOS, but not in Gnome, because they actually cared about users. Quite a cynical marketing strategy.

Another frustrating point was a Gnome developer liking PopOS's tiling implementation, then contacting PopOS to see if they'd be interested in collaborating on a similar - but dumbed down - implementation to use upstream. S76 refused to work with them, and fair enough, Gnome certainly isn't entitled to help from S76, but afterwards S76 on multiple occasions said Gnome simply didn't want more advanced tiling or were hostile to the idea- something clearly not true since Gnome expressed an interest.

When there was design changes to Gnome 40, Jeremy Stroller of S76 became angry and said he "didn't consent" to these changes, as if Gnome should be ran by System76, not the Gnome developers themselves.

To be honest, almost all of it comes down to Jeremy Stroller specifically. And even System76 seems to have quietly accepted that, as he has moved away from OS work to firmware work.

But I'm getting quite off topic...

When I've tried the PopOS alphas, it was still janky, but I'm sure it'll be far better in future, it's an alpha after all, and they're undertaking a huge job. Some of it seems really cool, and I always love fresh projects that are free of legacy cruft. I'm not sure it's for me, though.