@hankg Sorry, but I'd just like to interject for a moment.

Android uses Linux as it's kernel, but don't forget that Linux is only a kernel.

As you've probably now realized, there is terrible, terrible confusion caused by people referring to GNU as "Linux" and one consequence is that people can't understand the difference between GNU/Linux, BusyBox/Linux, systemd/Linux and Android, although all of them have Linux in them.

The issue seems to be that Android manufacturers go and modify Linux to support the hardware and then proceed to infringe copyright law by infringing the GPLv2, by not making available the complete corresponding source code of their modifications under the same license (neither up front, or by a written offer).

As a result, updates to Linux and then by consequence the rest of Android is dependent on the manufacturer releasing updates - and really they only want to fix their dirty patches that graft a mess of proprietary software on once of twice for a few updates and then they stop and tell you to buy the next product.

There is an improved version of Android called LineageOS that provides regular updates for many devices (including all the Pixel's), but unfortunately they can't stop themselves from leaving a lot of proprietary software in that shouldn't be used and only up to a certain version of Android can be supported with devices that have proprietary drivers that depends on the ABI of a certain version of Linux.

Thankfully there's a patched version of LineageOS called Replicant which removes all the proprietary software, but unfortunately device support is limited.