I would not want to live near a large urban area that was without power for months or even weeks.
Taking out nine substations doesn’t take out electrical production capacity. It makes it more difficult to equalize generators with users. It could lead to rolling blackouts, brownouts, manual equalization efforts, and things like that. A complete shutdown of all electrical generation in the US for a year and a half simply wouldn’t happen. These stories are fear mongering, not legitimate disaster planning.