Just got a steam deck and immediately checked out the desktop mode, and I was somewhat surprised to see KDE and pacman as opposed to GNOME and apt, I have nothing against the former though a strong preference for the latter, anyone know why Volvo went in this direction?
Games need to live closer to the bleeding edge than a lot of other software.
Also, for wine/proton, and the other customisations built into the deck, it makes sense to pick a starting point that is more built for customisation. By that I mean there was probably less things they needed to add or remove at the start.
As mentioned, it’s also likely there was personal bias internally. But even that can be a valid reason as they need to be familiar/comfortable with the starting distro.
Not saying that Debian cannot do it, but doing it this way probably made valve’s employees lives easier.