Counterpoint: Flatpak doesn't really solve anything, and I have no reason to use a Flatpak'd version of a software when there's a native version in my system repos. A lot of people feel this way: they see it when Flatpak doesn't adopt their native system theme, they see it when they try opening a filepicker and it starts in some esoteric location, they see it when they want to edit files of a Flatpak'd app and need to spend the afternoon locating it's binary. There are so many papercuts, bugs, regressions and failures on Flatpak's behalf that I don't think anyone would really want to adopt it unless they were forced to.

I speak only for myself, but I will never enable Flatpak on any of my devices. A lot of other Linux users share the sentiment.