Ovum reckons revenue from voice will start dipping within two years, and the increasing data revenues won't be enough to replace it either. That's not to say that people are making fewer calls, but in developed markets we've long seen voice traffic rising as revenue remains static. Ovum's latest predictions are based on that …
Predictions are easy
* Customers will whine about the price.
* Operators will whine about the price.
* Ofcom will whine about the price then force a change that neither the customers nor the operators like and that, frankly, no-one really understands.
Not about "subsidisation"
Voice doesn't "subsidise" data. There are two reasons voice traffic is lower than data but generates more revenue today. Voice bytes cost more to carry than data bytes because of the heavy quality of service guarantees required to make voice workable (and meet standards agreed with Ofcom and with other operators). And voice bytes are worth much more than (most) other bytes: people value voice highly and are willing to pay more for it. Both those are changing, of course, which is what is leading to the effect Ovum predict but it isn't true that voice "subsidises" data in any meaningful sense today. They are different services, with different costs and different values. And, in today's mobile networks, they are even carried over different network resources in many cases.