[bluGill]

The problem is you are assuming you can do that. Not everything is connected to the internet, and there are backups. You can probably shutdown power for a couple days (and a couple more weeks to be back up to full power), but you can only pull that trick once or twice before they start taking action. It isn't hard to disconnect internet cables (shut down all internet and force the operators to use personal cell phones...).

Likewise, water processing is mostly pumps. Even better, any competent town has backup generators and they keep a few days of fuel on hand, so even if you get the grid down there is water, and the system can function without internet.

That isn't to say you can't annoy life for everyone. However state collapse won't happen because of that. More likely you firm up the resolve to fight.