I'm not sure anyone can touch Android now. Android has more than 50% of the US smartphone market. To be exactly, it has 52% of the market.
And even if Apple does start making its iPhone available on all the major networks this year, it'll be a tall order for the iPhones to make any kind of a dent. Android has such an advantage in the number of not only carriers but the sheer number of different models available catering to a wider consumer preference.
The dark horse is Google's acquisition of Motorola and what that might mean to LG, Sony, Samsung, and HTC. I reckon Microsoft is busy courting them now.
One thing is certain. Motorola is Google's official Android maker. Just how Google will play favorites with Motorola will be know over the next year. Remember that Google worked closely with Motorola on Xoom. There is already a relationship there that no other carriers have.