[Gigachad]

They have a custom window manager because they had to build a controller friendly UI from scratch since one didn’t exist already. Not because existing DEs are broken.

Their package management also isn’t that exotic. It’s a lot like Fedora Silverblue where the OS is an immutable image and user software is installed with Flatpak.

[Manfred]

I'm not saying existing desktop environments are broken, my point is that SteamOS does not show that KDE / Gnome / etc are "mature" because it doesn't actually use them. In the same way that we know all dogs are good dogs but my house doesn't show that because there is no dog here.