Fortunately, Google slowly seems to be turning that around as of late. In the past few weeks, Sprint has added the Galaxy Nexus, LG Viper 4G LTE and LG Optimus Elite to the Google Wallet-supported devices stable, signaling an important growth in support for the payment system.
Sprint, of course, is an exception. Rival carriers Verizon and AT&T have been pretty lukewarm on Google Wallet on the whole, for reasons that have to do with security as they do with financial disincentives. The two largest carriers are founding members of ISIS, a rival mobile payment joint venture that also counts Visa, MasterCard, American Express, and Discover among its ranks.
Clearly Google has its work cut out for it on the mobile payment front.
Support for Google Wallet is being bolstered on the merchant side as well. Both Duane Reade and frozen yogurt-dealer Pinkberry have worked out marketing deals with Google Wallet recently.
But the obstacles Google Wallet and other mobile payment system must topple are real ones. To offer a purely anecdotal and personal example, I own a Nexus S, the first phone to feature support for the app, and I've never really even considered using the device to pay for anything. This wasn't out of some Luddite-esque disapproval or paranoia: I just forget that Google Wallet exists, even though it's on my phone (and I can't uninstall it).
This is a big deal, and a big part of the reason why mobile payment services have yet to take off. It's more than just having a phone with Google Wallet installed on it; users have to have a reason to use it. Adding more supported devices, then, is just half of the solution.