> Furthermore, dumped-over-the-wall projects like Android would be better referred to as "Shared Source" (with its association) - the Free branches are seemingly unable to actually keep up with the master!

That's because AOSP by itself is Android without all the integration work that's necessary to make a useful image for a specific device, and traditionally it's been a lot of work for each new version. Things are better in that respect since Android 8.0, which I think shows in frequency of both manufacturer updates and community builds.