"There's a very good chance that without it being open source it would have went precisely nowhere. "
Why? You say a lot of things, but none seem to related to why this is true. As far as i can tell, it is definitively not true.
The app developers were happy to go where there was money, and the users certainly didn't care.
Again, i'm a huge supporter of open source projects, i donate to the FSF, etc. I would love for it to be the case to say that Android was a success/failure because of open source. It's just i've seen exactly zero data that supports this notion, and a lot that doesn't.
The real history rewrite here is the rewrite that Android didn't enable choice or competition. Before Android all of the systems you're talking about had user interfaces that were tightly controlled by the carriers right down to the Verizon internet browser. Your best case scenario would be apple winning. Your worst case scenario is you still have Verizon deciding what your phone user interface should be like.