Most places prohibit this for a reason, not just caprice. Cables are buried under the streets. If you had five local cable companies instead of one, then you have five times as many street-digging projects and five times as many patched-over paving jobs.
Assuming you have enough competition, some of those companies will go under and leave your city or town with this mess on their hands.
Not sating I think this is a *good* reason, but I keep my TV to that "off" channel anyway