I still disagree with play services because it wouldn't be that hard to force manufacturers to support updates when you command such a large part of the market
There are these things called contracts, and if there are clauses for an OEM to be allowed to have access to Google services, Google lawyers could certainly add a few more sentences regarding compulsory updates.
Android isn't open source, except in the hearts and minds of fanboys everywhere. =)
Good luck getting all those apps running without Google services, or getting the devs to re-written them to use alternative APIs.
It only works in countries like China because of the way the government controls everything.
I pretty much doubt anyone cares about Amazon or Jolla's fork, or cared for the Blackberry's one.
It is just about not caring one second to enforce updates.
Google making Google play services was a natural reaction to manufacturers never updating Android on their phones for years leading to all kinds of vulnerabilities and bugs on Android that kept it far behind iOS in quality and features. Lets face it - Android used to be sneered at, the red-headed problem-child OS that used to the butt of jokes till it grew out of puberty and pimples in Ice Cream Sandwich. If manufacturers had truly honoured OS updates, Play Services may never have been built - it allows Google to update Android without updating the OS. And yes, they will retain full control over Play Services - I completely understand the need to fully possess it and ensure a high level of quality assurance.
Also blaming the fall of CyanogenMod on Google is ridiculous. CM fell because of mistakes made by Kirk Mc Master and several others. He attempted to be a dictator even going to the extent of banning OnePlus phones selling in India - this was fought and resolved in the courts. All goodwill for CM was destroyed. OnePlus ditched CM and moved to Oxygen OS. CM had a stroke and died. Now Lineage is the new shiny OS rising from the cooling corpse of CM.