Canonical wants some corner of the ecosystem where they can say that they are driving the progress instead of being just downstream consumers and (re-)packagers.

And to be honest, Snaps had fair chance of succeeding; when they first were released flatpak was still pretty young. Docker has had its own issues, and podman (etc) is even younger yet. If they played their cards right Snap could have been Canonicals chance to shine, and I guess they know it and are still trying to salvage the effort.