Oh this is interesting, that extra 25% didn't taken from iOS.... but from Symbian.
I don't think there will be monopoly, at most it might look like "Windows monopoly" which is not really monopoly but domination and it's far from that. Because Apple do better in app market and Android and Windows addiction is build on top of software dependency (Games, Office etc.) not to mention iPhone it self do a hell lot better then Mac.