Well, I didn't know about it until today. Sorry :/
The thing is, why do Google have Fiber in Austin, but not New York or LA?
Why not? Here's why.
The reason Google Fiber went to cities such as Austin, Kansas City, and Provo was because their infrastructure had already supported fiber cables far before Google had setup there. Due to this, fiber connections were already established and Google was just able to buy use of the cables from their respective cities which would allow testing of the technology to proceed at an accelerated rate without unnecessary spending regarding wiring the entirety of the city with fiber cabling.
In larger cities such as Los Angeles or New York, this type of testing could not occur without a large amount of work being done first. Not only would construction cost a large amount, but Google would have to be granted permits for work to be done in each part of the city, or in the case of New York, each borough. This would not only increase Google's expenditure but increase the amount of time required for the project to proceed. By this time, it could take months to receive the permits. After all the permits come in, Google will have to hire a private contractor to rip everything up, insert miles of fiber wiring, and patch it back up again.
By the time this takes place, the project could have taken well over a year to a year and a half. If Google started this project last year, it wouldn't start testing until 2014. By then, the entirety of the city will know Google is up to something and tell the media. Media reports will allow ISPs to find out what Google is doing, and then just be able to compete with them before they even get the service up and running.
tl;dr: Google would spend money and AT&T would already be charging you more for the same internet Google could provide a year or more down the line.
Or this will suffice:
building an internet infrastructure isn't easy. they can't just use, say, time warner's fiber optics in NYC, obviously because it's a competing service and it'd be just problematic. they have to lay in the fiber optic lines and route them across the country. they're basically building an entire network.
