I suspect that eventually we're going to start integrating chip-scale atomic clocks[1] into our mobile devices, which will allow a much longer synchronisation period. Right now they're still ~35g and ~130mW power, but that's only going down. There's going to be a whole bunch of interesting new distributed processing stuff you can do with highly accurate synchronised nodes; something like the Google Spanner system on a more local scale, perhaps.

[1] http://www.symmetricom.com/products/frequency-references/chi...