That's not really true. Ffmpeg is a Swiss army knife for anything related to digital multimedia (old and new). It is broken into a few libraries but doesn't really have plugins.
Gstreamer has a different model, chaining together plugins. Lots of overlap, but I think Gstreamer only has real traction because some silicon vendors use it.
I didn't watch the whole video, but the quick summary is that because of passive investing (index funds in 401ks, etc...) lots of regular people will end up owning SpaceX stock even though they didn't explicitly buy it.
It's really not a replacement for Google cast. It requires actively encoding video to send over wifi. If it's anything like wireless Android Auto it will eat a lot of battery. Google cast is usually a tiny payload to the device to start playing some URL from the Internet.
Will demand for computing ever go down from where it is now? Even if the AI bubble temporarily pops, in the long run I think the demand for computers will be practically infinite.
Market forces will probably bring the price of hardware down in the next decade. Whether it is in a form that is useful for regular people/hobbyists is another question. If not, then hopefully the "cloud" starts to look a lot different.