What makes this possible is the long lead time required to manufacture those really big transformers. Hopefully it will be possible to make them via 3D printing before the trouble starts.
My present ball-park guesstimate for fatalities if this goes down is @ 40 million +/- 20 million, mostly in the BosWash corridor. No power means gas station fuel pumps won't work means no food transportation and no water pumping, let alone sewage treatment, plus people can only get around on foot.
Millions will die horribly. This is not anything anyone sane wants, and I hope it never happens.
But I think it will in the second term of the next Democratic President given the way things have been going.
I assure you both sides have guns and leftists are itching to kill