Comment by gruez
>If it's part of every modem/gateway router, there should be so much bandwidth it doesn't matter.
Why would it be part of every modem/gateway? Since there's no monetary incentive to participate, in all likelihood all nodes would be run by volunteers who are shelling out extra for a compatible modem/router.
Actually come to think of it, you can run a volunteer network providing internet connectivity with off the shelf equipment right now. It's called setting your wifi network to "open". Why don't people do that? How would your mesh network fix those issues?
Not only just shelling out more for that compatible modem/router, that volunteer would also have to be willing to set up at least the antennas in a place optimal for others to actually use it instead of potentially optimal placement for their own services. A client on the street is not going to get good connectivity to someone's cell repeater tucked deep in their media cabinet next to their game console and under their TV in the center of their home. You'll need to get your volunteers to bother placing these antennas on their roofs, on the top of flagpoles, etc. to get good propagation. They better have properly grounded it as well and put fourth good lightning protection for this new wire high point at the top of their home.