This will lead to complete anarchy in certain areas
Imagine Chicago...
If this goes on for more than a month, this would lead to an all out civil war. However I think that would require an EMP attack rather than a hack attack.
Personally I'm anarchist, I think it's totally fair to loot stores in the event of a massive power outage, especially when there is no way you're going to get caught. This is going to hit everyone pretty hard.
I fantasize about forming a gang with my best friends and just going grand theft auto on motherfuckers but I know that's really unrealistic. You would probably see military vehicles patrolling the streets everywhere honestly.
Also what about when the lights come back on, we would be living in a police state at that point.