A couple things to consider, as someone who works in the industry, and lives in New Jersey.
NJ has the highest population density (1189/sq mile)
. It is surrounded by two major cities (New York and Philadelphia).
AT&T is not based here, but they used to be, before SBC bought and renamed themselves. That company is now based in Dallas. There are still a lot of AT&Ters around the state in large facilities. This doesn't really matter though, considering AT&T probably provides local access to less than 1% of the NJ population.
Verizon is based here. Their actual headquarters is located in New York City, but all of the executives sit in Basking Ridge, NJ. This is important, because almost all of the Verizon employees at a director level and above are now in New Jersey. Different from AT&T, they are the local telco in almost every town.
Comcast is based in Philly. Lots of Comcast employees live in New Jersey. Comcast is a major cable franchise in NJ (as it is in most places).
The state of NJ, a few years ago, granted Verizon a state wide video franchise.
This is a big deal. It means that Verizon can offer FiOS everywhere in the state without negotiating with the 566 different municipalities in the state
. (566 municipalities for 8.8 Million people - NJ is a a good example of local government gone awry. Compare to 351 for 6.6M in MA, or 482 for 37M in California)
As the result of the above, FiOS is available in most towns, offering 20-50Mbps internet. Comcast Xfinity offers their highest tier service wherever there is FiOS, so nearly everyone in the state can get fast internet if they're willing to pay $30-$60/month. Notice to governments: reducing the amount of regulation (state wide franchise) can create more competition which can yield better results for citizens.