As long as Android and iOS both remain strong competitors, neither can really be seen as a smartphone (or tablet) monopoly. This is part of the reason I think Apple going "thermonuclear" on Android is counterproductive for them -- if they succeeded beyond their wildest dreams and Android disappeared tomorrow, Apple would essentially be assured of having the government (not just the US, but perhaps even more so in Europe) come in and force them to open up iOS far more than they would be comfortable doing.
Now we have a variety of devices and platforms and I think it's fair to say that there is no comparable conglomeration of power in the industry. Not yet, anyway.
This doesn't mean we wouldn't be in the old IE monopoly of "nobody downloads browsers"
Plus, you can have a different browser on both the iPhone and android.