Poor planning, plain and simple.
I work for a major financial institution on the street. Various facilities were swamped, and we never missed a beat. What, were we just "lucky?" I don't think so.
Starting a week ago we had disaster crisis centers setup.
* Every few hours all East coast facilities reported in any issues
* Inspection and testing of all critical systems ahead of time
* Stockpiles of supplies on hand
* Prefail over to DR where possible
* All hands on deck to respond
Sadly, if you want to be prepared, you can be. If tons of money is on the line, then the price of being prepared is well worth it. We test our systems continuously year round. We have disaster recovery drills at all facilities multiple times a year. Departments' rating depend on how well prepared they are for things like this.
And don't throw that "1888," "worth storm ever" crap around. This is Wall Street. Manhattan. Terrorists have tried to blow it off the map multiple times. Several hurricanes have hit this spit of land that sits a mere few feet above sea level in the last decades. A hurricane hit and flooded parts last year even! If you did not prepare for this including flooding and sealed underground tanks and sandbag walls, it was your own fault.