Yes, but under treath of lawmakers mandating a single standard. And the EU has now forced a single standard anyway on smartphones, tablets, etc.
Although I agree that there are quite a few examples of a "naturally emerging" single standards without lawmaker intervention, but this is not really one of them...
Indeed, the law applied to all manufacturers, but no other manufacturer wanted to remain with microUSB Type-B 2.0 due to economies of scale, etc. The loophole that Apple used was available to everyone anyway, so it's not like they couldn't have followed suit.