If you iMessage iPad and/or iPod Touch users, all that is required is that they be connected to the internet (w/ their built-in wifi). This is how I probably communicate with up to two dozen family, friends & co-workers every day. Works like a charm when I can't simply call via phone/cell.
Apple doesn't maintain cellular or data networks, btw. That's up to the ISPs & big telcos.
You have jumped to a conclusion and are pointing fingers based on an assumption *you* have made, generalizing from what you want the system to do for you, not from claims Apple has made.
As embarrassed as I am for defending Apple in this case (they have too much money to be defended), you have definitely missed the boat. It helps to learn more technical and logistical details before you spout off on the interwebs.