Except that Snaps and Flatpack are over-engineered inflexible garbage compared to how this is handled in sane environments. Flatpack can't even handle the concept of installing to different media without building a brand new repository on it FFS (I don't know if this is true of Snap because it is far too Canonical-centric for my tastes). There's no reason it has to be like this.

Even AppImage is slightly over-engineered in my opinion, but otherwise the only real failing of it is that since there's no standard for ELF embedded icons (wtf is wrong with UNIX devs!?) it's a shit-show to get them to show up as anything other than a generic one.

This isn't hard, Linux people. Just standardize on a set of core libraries and stop breaking ABI outside of major versions, then you'll magically have this thing we call a "platform" upon which applications can run without being recompiled.