Android being an open source OS is nowhere near as easy to install as a regular linux open source OS.
I've been trying to get my own android / androidTV box working on popular hardware like rPi and other Amlogic, Allwinner, Mali based boards without much success. Even devices manufacturers have troubles with the same (talking about SBCs here).
Android is open source only for name sake. Google's deliberate control over the entire Android ecosystem is undeniable.