I believe the answer is that it is basically a pipe dream. For some reason, these sorts of ideas infect people with breathless enthusiasm. Telcos won't be necessary anymore, the reliability will be so much better, etc. Of course the reality is different. There are technical reasons for this, such as mentioned in another comment, but what I also think is important is the human factor. People would have to be convinced to administer their mesh nodes, and of course there are network effects here (there's really only a point to this if there's a critical mass, at least around you). When you think of the average user what they really want is to pay some nominal fee to ensure that the maintenance of their uplink is Somebody Else's Problem--they don't want to reconfigure their mesh node just to check facebook &c.
