TeliaSonera is an example of a forward thinking operator that has implemented IPX and now runs GRX services over IPX. See What's IPX for a discussion of IPX.
When the number of operators and carriers supporting IPX reaches a critical mass, those without will left behind as they cannot meet the need for assured quality of service and service classification.
The rapid growth of smartphones, machine-to-machine applications, and the Internet of Things will quickly reveal areas of weakness on the networks.
The GSMA has a new initiative called Network 2020 that addresses the ecosystem needed for an all-IP future. See the Telecom value chain: analysing the opportunities presentation from the GSMA IPX Summit 2013 for further details on IPX.