It’s because Canonical has a vested interest in pushing the solution that they spent money developing.
As much as I appreciate everything that Canonical has done for Linux, this is the problem with trusting for-profit companies in the open source realm. Profit is their motivator. They don’t care that flatpak has better performance than snap, they just know they spent money developing snap, so they have to force it onto their users, despite it being the inferior tech.
Swedneck