Part of the problem is that a lot of time, personnel and equipment had to have been used for rescue as opposed to delivering supplies. If the state and locals had done a better job of getting folks out who were otherwise unable to leave, and if folks who were able to leave had been smart enough to do it then the supplies might have been delivered quicker.
Having thugs shooting at the helicopters, boats and police on the ground may not have been factored into any disaster relief plan. It certainly held up rescue time.
I haven't seen any TV pictures of the 150 or more school buses sitting fender high in water, unused for the evacuation of people without cars. Nor have I seen more than once the flotilla of shallow water boats that arrived quite early only to be shot at.
CNN had a summary type show tonight. They made it seem that the looting started only after the city flooded and they failed to mention the shooting at all. Revisionist history is starting already.