Even worse, a text doesn't even put a load on the network. It packs your text into unused space in the signaling portion of the protocol, packets that would have been sent anyway.
Only a matter of time until someone figured out how to make money off NOT charging for access to a free capability. Apple will make millions just off of “it’s free on iOS and your friends are already using it” hardware sales.
That’s been the problem: ubiquity. There’s enough iOS users to make transitioning from SMS easy; few others can provide that “everybody is doing it” base.