I am beginning to think that plain old acts of sabotage from sleeper cells entering the US everyday in the name of diversity combined with cyber attacks will be the way this happens. Many of our enemies best attacks have been low tech use what you have and be damned the losses as there is a greater like awaiting you in paradise. With most of the biggest transformers now made in China you can be sure they will turn the screws on us. I have no doubt that we would in the end overcome such an attack, but the cost would be great.
The Northeast Blackout from a few years ago comes to mind.
And that wasn’t even sabotage.
Yep, we have a pretty exposed system of uninsulated above-ground wires and cyclone-fenced substations. Mainly unhardened, open to many forms of assault, from nature or men.
We’re able to go for a couple months, but even that takes planning, rotation, etc. Having propane (tank kept > 40%) heat + gas log, well & generator, and being very near game & fish would help some.