As for the reason why they won't do fireworks, if you just paid for repaving or your driveway, would you want a hoard of people standing on it for an hour straight in one spot, causing new depressions in the fresh pavement? Walking is a lighter pressure experience to the surface, standing is long term pressure.
That being said, they will only close sections of the street at a time - kind of like road construction on major highways and city streets.
Dreams is right - it is the slow time and folks going to WDW will experience similar types of things at this time of year (they are taking their Space Mountain down soon for refurb, but protests are so bad, they can't give it the overhaul that ours got).