That Android would be free if you replaced the non-free parts by free ones is obvious and does not make it actually free.
> Also many people buy windows license separate from their device. Google surely does not want situation where people buy google services license... they want mass adoption for data collection.
> If google starts to charge for android then i am sure there will be manufactures selling phone without OS.
None of this matters for the question at hand which is if Android is free.