When Verizon started deploying FIOS in NH they started in towns with economic potential (of course) and also where ready access to long distance backbone fiber existed.
Installing FIOS is not just a matter of wiring up the area they also need to connect to the backbone.
I assume decision to deploy FIOS is a complex mix of business, engineering and manpower planning.
Out here in the Boonies this area is supposed to eventually get FiOS, But no idea of when, At least this area can't be sold off like Maine, As Barstow CA is too important for their West Coast to East Coast operations to sell off. -- (14.70GHz crunchin 4 SETI w/the PC Perspective Killer Frogs)