Canonical has a history of ignoring established practices and established software projects in the FOSS community and instead rolling their own in-house competitor behind CLA licensing agreements that make it hard for community developers to contribute. It feels like an embrace-extend-extinguish situation to me. They did it with Unity (replacing GNOME 3), Mir (replacing Wayland), and now Snap (replacing Flatpak). There are also technical reasons why many Linux users don’t want these userspace/sandboxed packages (Flatpak and AppImage included) taking over the position formerly occupied by native distribution packages (.deb, .rpm, pacman, apk, etc) because of issues with unnecessary copies of dependencies and poor integration with the rest of the system. These concerns apply to Snap as well, and Ubuntu has been pushing to replace .deb packages with snaps.