If Apple pushes this into all there devices like they're doing, we can eventually be done with the phone carriers.
I read the rest of your post as well, but I'm not quite sure what you mean here.
Mi-Fi still piggybacks on a wireless carrier. As of yet, wireless service off the cloud is tremendously impractical and dependent upon giving up privacy and network security.
A third party of one sort or another is needed, especially because while some major companies could conceivably set up wireless repeaters for their own private WAN's, it's very impractical, a waste of bandwidth and pretty much impossible for individuals to do point to point.
Whatever you want to call it, fundamentally some central carrier with a switched network will be part of the picture... until you can have cell phones that can transmit a signal to any point in the world under its own power without repeaters... and also not fry your brain cells with the dBm of signal output required to do so.
And then you've got carriers on the other side... If you're talking to some guy on his laptop via iChat, and he's not using a 3G or 4G card, he's sitting on a wireline network of another carrier... unless he strings up his own fiber network to talk to every conceivable person around the world that he wants to reach, or uses longwave radio with all the required operator licenses, he's stuck with a carrier.
What may change is the way carriers bill for access to the shared PSTN... i.e. soon, voice will no longer exist as a separate category and everything will be billed as data, either flat rate or by usage.
The unfortunate reality is that the regional carriers, while competitive, are still dependent upon the large switched networks of the Baby Bells... an infrastructure of billions upon billions of dollars that took many decades to build out to where it is now. For any enduser provider to not have to lease lines from an upstream, would pretty much require them duplicating the entire infrastructure.
