And also excluding all contactless cards.
Someone posted his experience to another thread about getting NFC support for his point-of-sale terminal. His payment processor bundled the reader with the NFC option with extra services, and the net result was it would cost him $100/month extra to support contactless cards, Google Wallet, and

Pay.
When faced with that kind of decision, I can understand why a small business would forego NFC support. Their PoS terminal is essentially self-contained, and there's not a lot of risk as long as no one in the chain of authorization is retaining the credit card information.
But, larger retailers have their own PoS systems, and the entire path is not necessarily secure. All it takes is one breach like the ones at Target, Home Depot, Neiman Marcus, etc. and the costs of compliance and bad press can far exceed the incremental cost for supporting NFC.
As someone else pointed out earlier: all it will take is one large breach at a big retailer, followed by widespread media coverage that points out that

Pay users weren't exposed by the breach due to tokenization, and big merchants will be falling all over themselves to implement NFC.