It only makes sense, considering that the Nexus 4 seems to lack LTE to make carriers happy, who would demand many more design + software changes to Google’s “pure” Android experience in exchange for LTE.
So, in the most Google-like of ways, they decided that if they couldn’t actually work with someone, they may as well go it their own way. Unfortunately, they are going to have to lose everything they built - especially their big market share - because the status quo demands that Google not have more control over Android devices than carriers do.
Why take on such a risky move? Because Google made a gambit that turned out to be a mistake. They decided that they would cede control in exchange for market share. Now that they’ve kicked butts at that, and it’s turning out to really only be profitable for Samsung, and it’s turning out to be kind of terrifyingly bad for Google’s project of refining and controlling the Android experience, they’ve had a change of heart. They want the control that would let them build an incredible Android device. And to do that, they need power.
So they’re thinking of building their own network to generate that clout. But they’ve got one big problem: while this network is getting off the ground, it will force them to cut their ties with the existing carriers. Adoption rates will plummet. Revenues for Android device manufacturers will plummet. Availability of Android devices will probably also plummet.
Which leaves Google with what clout, exactly? You might think that they’ve got a ton of existing Android users, and they must be valuable! Yeah, read: tons of customers locked into existing contracts, who are more device-agnostic than they are provider-agnostic. They will leave Android phones before they leave their existing wireless providers. Churn is about 0.84–2% per year depending on the carrier, but device replacements happen at a rate of closer to 50% per year, thanks to the 2-year contract. So, again, carriers have all the clout, and Google’s market share is a pyrrhic victory - a number that doesn’t matter to anyone’s bottom line.
Which really does underscore why they’d be building their own network: Android is essentially worthless to Google as it currently exists. By building their own network, where they’d eventually build up some sort of sticky subscriber base, and where they’d have the freedom to create a better Android phone, they would add a lot of value to the Android ecosystem.
This is ultimately a sign that Google’s moving away from having market share as a goal, and closer to having profitability as a goal. It’s a sign that Apple is winning in all the ways that matter, because Google is now pursuing their model. And it’s a model that Google is going to have to pay dearly for, despite all they’ve already spent on Android. They’re playing a new game now, and it’s not an easy one to win at.