Exclusive franchises, building permits, neighborhood associations, etc. Comcast, Time Warner Cable, and AT&T have been playing this game for a long time. It'll take fighting through tons of telco/cableco-paid for local laws for Google to get in anywhere; just because they've made it in one city won't make the next any easier (in fact, probably harder). I hope Google (or someone else) pulls it off, but it's not going to be easy by any means.