The amount of disk space used by flatpak is too damn high!
This is a common complaint.
Disclaimer: I am a huge proponent of flatpak and I have been advocating its use for a long time now. I still believe it is the right way to build, package and distribute applications, and whenever I’m given a choice, I install the flatpak version of an application rather than the package coming from my distribution.
Let’s observe disk usage on a real life example: my system.
The total disk usage for / is around 60GB! Over half of that (35GB) comes from /var/lib/flatpak. Within that directory, almost 20GB of data comes the runtime subdirectory. Let’s have a closer look at the largest bit, /var/lib/flatpak/runtime/org.gnome.Sdk.
It sits at 8GB and contains four versions of the SDK (3.36, 3.38, 40 and master).