This is true of every aspect of this, even the first disaster declaration - the Governor of the state has to request it. Jeb Bush did so right off the bat last year, and that was one of the reasons Florida (although our disaster wasn't on this scale) got help so quickly. Plus, of course, he had a plan.
I'm sure that the investigations will show that NO and LA had very elaborate plans in place, too. The difference between them and Jeb Bush is that the LA folks had no idea how to actually implement their plans.
As we've already seen, they have fools in leadership positions, and the "action" slots were probably patronage jobs, which means that there were incompetents there, too.
This stuff built up over decades, though -- it'd be really tough to lay blame only on the current state and local governments.