The majority of Linux distributions out there seem to be over-engineering their method of distribution. They are not giving us a new distribution of Linux. They are giving us an existing distribution of Linux, but with a different distribution of non-system software (like a different desktop environment or configuration of it)
In many cases, turning an installation of the base distribution used to the one they’re shipping is a matter of installing certain packages and setting some configurations. Why should the user be required to reinstall their whole OS for this?
It would be way more practical if those distributions are available as packages, preferably managed by the package manager itself. This is much easier for both the user and the developer.
Some developers may find it less satisfying to do this, and I don’t mean to force my opinion on anyone, but only suggesting that there’s an easier way to do this. Distributions should be changing things that aren’t easily doable without a system reinstall.
I do agree with you that it’s a cool option. It would require a distro to prioritise that and architect that in a way that seamlessly switches. Maybe there is a gap for something like that if the UI is nice.
Actually, on reflection, I think Mint did have an option from login screen to use KDE or Cinnamon.
It wouldn’t require from the distro any more work than they do on their current package repository. A DE and it’d configuration could be debian packages just like any other.