Flatpak also has a variety of disadvantages, such as creating a unsightly blob that's a few gigabytes large.

Delta updates are reliant on the abilities of the packer, meaning that if they're lazy, it'll be completely useless for those with metered connections due to data waste.

Managing anything lower than surface level is a complete byzantine [INSERT SWEAR!] due to the way the CLI worked, meaning if you wanted to clean up post install packages, you better get cracking into some obtuse commands.

Flatpaks do pull their own libs, but this can lead to a lot of tacked on dependencies and redundancies. So if someone's terrible build system is pulling libcrpyto-1.0.0, then you can feel warm and fuzzy about that newly introduced security hole.

Flatpaks are often out of sync with upstream updates and until recently, were more single source than central repository, a flaw shared by PPAs, meaning that if the source went offline, well too bad for you.

Other than your delta updates comment, your post is absurd. I'm not even going to bother responding to those other points you made. Anyone who knows what GoG currently do and how Flatpak compares to appimage, snaps and per-distro packaging formats will read what you've written and instantly disregard it. Your post is particularly absurd when you consider that some of your negatives are found equally or worse with Appimages.

Maybe you should take a look at this bug report.