They don’t need to blow up NYC ,, they picked the wrong target in the towers... if they had destroyed the telephone exchanges and IP connectivity at the nearby ATT switch hubs it would have done much more damage to the US economically.
The Islamic fanatics need to eliminate NYC because of the symbolism. It wasn’t long ago that they could have shut down much of the power in the Northeast for an extended period. In each case they’ve attacked something that is symbolic to them. If they ever become truly rational, we’re totally screwed.