I think Red Hat should really be stepping up more here, especially since with RHEL 10 they stopped maintaining a ton of desktop packages with the advice for users of those packages being "get the package from Flathub instead of from us" (see https://docs.redhat.com/en/documentation/red_hat_enterprise_... , search for Flathub). If that's Red Hat's attitude towards desktop software, they should be providing the resources to make Flatpak a viable alternative.
> A user's Linux distribution may still be providing an older version of Flatpak that does not have support for --device=input, or whatever new feature that a Flatpak developer may wish to use. Wick said there needs to be a way for applications to use the new permissions by default, but fall back to the older permission models if used on a system with an older version of Flatpak.
I'm glad he brought that up as a problem. I maintain a game on Flathub that has audio and controller support. Because of the limited permissions granularity, that means that the game is displayed as requiring arbitrary device access (--device=input is too new, so the Flathub maintainers don't allow it in packages yet) and being able to listen to your device's microphone (the audio permission doesn't allow only accessing speakers but not microphones). I hope that Flatpak adds backwards compatibility for permissions so newer Flatpak versions can start having more granular permissions.