You can track the bug history here:

https://bugzilla.mozilla.org/show_bug.cgi?id=1751363

You can see here Chromium had support for this for several years prior:

https://aur.archlinux.org/cgit/aur.git/log/PKGBUILD?h=chromium-vaapi

Android being based on Linux prob has something to do with Chromium's strong Linux support, but Mozilla has consistently prioritized Windows/Mac. Despite it still be challenging, building Chromium from source has always been a lot easier IMO than trying to create a custom build of Firefox.

Regardless, when it comes to privacy, Chromium itself is pretty stripped down and has policy-based integrations that put it on par with Firefox in terms of security. Even with Firefox, you'd have to modify quite a few policies to improve security. Tor/Mullvad Browser though do a better job in many ways and there is no equal to those privacy enhancements on Chromium that I know of, unless you're using something like GrapheneOS.

Point being, people like to complain about Chromium a lot & act like Apple fan bois for Firefox, when in reality privacy is nearly the same with both with some minor configurations.