Well… Flatpak ships Propietary Software too. And at this point Propietary Software is almost avoidable (unless you have a LibreBoot. I want one too). But it’s reasonable to be frustrated that an operating system as influential as Ubuntu has ended up falling so down in its technology, and that it has the support of a company like Chanonical.
Edit: Thank you for the comments. I didn’t noticed Snap itself is propietary.