Android was already a platform on life support. Google has wielded its authority to dictate how apps should behave such that even 3rd party stores do not stray far from Google's rules. Users of android phones have little hope to run a program from 5 years ago, or to roll back a bad update in an era full of bad updates.
Why don't you go back to 2006 and tell me which complete open source mobile OS you want to use.
An immense amount of time was spent beating up vendors and others to be able to release, as open source, an OS that you could actually build and put on a phone. These were the days that verizon and AT&T and other controlled exactly what OS's were allowed to run on phones.
Even being able to unlock a bootloader was not a thing.
The only thing that has happened for "as long as i can remember" is that different factions of open source folks have never been happy with the precise contours of AOSP vs what they want, and choose to shit on the immense hard work of lots of people as a result.
Yet i doubt any of them would be close to where they are, at all, had android not been released as open source.
Can we please stop rewriting history because we have some disagreement with the contours. It was an immense leap forward for open source OSes on phones.
Apple released the iPhone and basically told all of the carriers "tough crap, you can't put your bloatware on our phones. This started with AT&T (exclusive carrier for iPhone) and by the time that agreement ended, every carrier was clamoring for the iPhone on their network. It was the next big thing after all. If you don't want us on your network you can explain to your customers why they can get an iPhone on a competitor, but not on your network." Vendors had no choice.
I dunno, Early iphone did not have the market share to command this in the way it does now. Android did fairly quickly, knocking off Symbian and RIM much faster and getting to higher market share much faster than apple.
Honestly, I think it was both in combination - and more particularly, that none of the up and comers (apple or android) were willing to accept control on the part of the carriers.
Back then Google was even bidding on spectrum :)
I'm unsure what would have happened if only one of android/iphone had existed.