Some of the problems described are problems with hardware specifications being unavailable.
Some of them, like the HDMI audio, is free software developers not paying attention to details.
And sometimes, your multimedia keys don't work because GNOME decided, in a minor release, to grab all multimedia keys in a way completely incompatible with all existing applications using them and in a way that required nontrivial integration with (at the time) unstable parts of the GNOME software stack and a new poorly-documented API, which changed again a few releases later.
Re: hardware support
Some of them, like the HDMI audio, is free software developers not paying attention to details.
And sometimes, your multimedia keys don't work because GNOME decided, in a minor release, to grab all multimedia keys in a way completely incompatible with all existing applications using them and in a way that required nontrivial integration with (at the time) unstable parts of the GNOME software stack and a new poorly-documented API, which changed again a few releases later.