Reminds me of https://xkcd.com/2347/

To my knowledge Fabrice Bellard created two of those (ffmpeg and qemu)

neither are maintained by a single random person in the middle of nowhere. more like thanklessly maintained by a group of enthusiasts.

but, more to your point (i assume), i suppose they could use more support, especially from large users like google.

Even YouTube?

As someone who once had access to internal fleetwide profiling information, yes.

There is older evidence based on quirks in encoding. https://multimedia.cx/eggs/googles-youtube-uses-ffmpeg/

Why would they use anything else? I don't think there's any other software close in terms of cost/features. (unless you count libAV, which is a fork of ffmpeg)

The tweet says yes.