Even if some technically inclined folk can install what they want, the masses will stay in the walled garden so that Google can get their cut and exert ideological control. Even now, both Google and Apple engage in practices across their product that are designed to scare people away from third party applications. From Google's terminology when describing Google in banners as "a more secure browser" etc, to Apple requiring a secret incantation in order to run unsigned apps.
All of this kind of mind control bullshit should be eradicated via regulation. Companies should not have a license to be deceptive towards their users.