Thank you guys for the enlightening discussions.
There are just a few things that I'm still not sure when it comes to the relationship between Google, Google's own version of Android (which is based on AOSP?) and AOSP itself.
My understanding of it is this, correct me if I'm wrong:
1. AOSP is based off of Linux kernel. Henceforth, newer Linux versions will have nothing to do with AOSP anymore.
2. AOSP is open source, and is maintained by Google.
3. Google's Android is based off of AOSP, and Google's Android is NOT open source.
4. The confusing part is this, which one does Google update first, AOSP or Google's Android? For example, Android Pie, does Google update AOSP to version "Pie" first, then update their own Google's Android? Or is it the opposite? My impression is, Google's Android gets updates first, then only AOSP. And lots of features are missing from the bare bones AOSP.
5. All current Android devices' OS'ses (Xiaomi's MiUI, Huawei's EMUI, etc.) in China or the whole world for that matter, is currently based off of Google's Android (not based on AOSP). Only major exception is Amazon's Kindle devices (which uses Amazon's in-house OS, based on AOSP) and also all the "custom ROMs" (based on AOSP) that private developers (normal phone enthusiasts, like you and me) make.
If my understanding is correct, then Huawei would still be forced to eventually fork their Ark OS further and further away from AOSP, because one can never be sure if Google will one day decide to turn off the tap to AOSP completely. But in the mean time, of course, Ark OS will be pretty much 100% compatible with AOSP.
CAUTION!!
All the above is just my understanding, please correct me if any info is wrong.
Actually, Google updates Android first, and AOSP only receives the update later.
AOSP is open-source, and it's exactly that, open-source. It can't be controlled by Google in the same way that Android is.