Haven't realized? Are you kidding?
They fully realized it. But they'd be first admitting to eating babies alive before they'd willingly talk about that. And they'll fight tooth and nail against anything that could come close to merging "phone" and "data". The reason is very simple: Phone IS already data to them. But data they can sell very, very, VERY expensively.
Ponder for a moment how much data a voice call is. Realize just how well it can be compressed.
Ponder for a moment how much you pay per minute for cell plans.
Now take a wild guess how expensive a kb of that data is for you.
Multiply by a few thousand and you come close to the real value of "voice data" to your carrier.