Even if you’re right about how software packages should work (I tend to agree), whether Flatpak should take on enforcing this model is a whole other question.

As far as I know, older packaging systems like dnf/yum and apt allow what Flatpak allows.

Maybe the developers just wanted to focus on being a good packaging system, which as we’re seeing is a hard enough job, and not on changing the permission model of packaging systems. Seems reasonable?