Free wireless broadband for everyone?

My first thought was that this news story [1] should have one of those TV sitcom laugh tracks:
 
A startup called M2Z Networks [2] wants to build a wireless network that will offer free broadband service to 95% of U.S. homes within 10 years.
 
(Insert laugh track.)
 
Basic service would deliver 512Kbps, which even for free isn't likely to set anyone's heart thumping.
 
(Insert laugh track.)
 
Building the network hinges on the U.S. government agreeing to give M2Z use of 20 MHz of spectrum between 2,155 MHz and 2,175 MHz -- give as in for free -- for 15 years. The company would pay the government 5% of whatever it might collect in ad revenue and from selling premium services to those who can't stomach the 512Kbps.
 
(Extended laugh track here.)
 
But then you get to the part of the story listing investors: Kleiner Perkins Caufield & Byers, Redpoint Ventures and Charles River Ventures. Sitting on the M2Z board are Kleiner Perkins' John Doerr, Redpoint's Geoff Yang and CRV's Bruce Sachs.
 
These are serious people. … They probably don't even watch sit-coms.
 
Maybe this is doable?