As far as I've understood, it's impossible to scale a flat mesh network, because of the amount of routing information required is quadratic in the number of nod

As far as I've understood, it's impossible to scale a flat mesh network, because of the amount of routing information required is quadratic in the number of nodes. To solve this, you need a hierarchical network (like the Internet has), however now it's no longer flat, and certain nodes will have more power/influence than others. On a global scale this will undoubtedly lead to similar political problems with control and privacy. Someone correct me if I'm wrong on the details here, but this is a network theoretical problem that needs to be solved before you start designing all the other bits and only realize much later that the network will be congested beyond usability for meshes larger than some trivial size.