Stuxnet destroyed centrifuges. It does not seem impossible that a sophisticated attack could shred some critical equipment. During the Texas 2021 outage -they were incredibly close to losing the entire grid and being in a blackstart scenario. Estimates were that it could take weeks to bring back power - all this without any physical equipment destroyed or malicious code within the network.
Edit: Had to look it up, the Texas outage was "only" two weeks and scattershot in where it hit. The death toll is estimated at 246-702.
The fact that the Texas outages killed anyone is a testament to the fact that the USA is, apparently, a developing nation, possibly going through a rough patch.
It’s not like there wasn’t enough generators or fuel in the nation to ameliorate that crisis. It was that, like all developing nations, resources are not available at the point of need despite their widespread availability.
Yes, there is the risk of cascading failures, some industrial processes are very hard to re-start once interrupted (or even impossible) and the lead time on 'some transformers' can be a year or more. These are nothing like the kind that you can buy at the corner hardware store. A couple of hundred tons or so for the really large ones.
Grid infra is quite expensive, hard to replace and has very long lead times.
The very worst you could do is induce oscillations.
Bloomberg had a decent article[0] about transformers and their lead time. They're currently a bottleneck on building. It wasn't paywalled for me.
"The Covid-19 pandemic strained many supply chains, and most have recovered by now. The supply chain for transformers started experiencing troubles earlier — and it’s only worsened since. Instead of taking a few months to a year, the lead time for large transformer delivery is now three to five years. " [0]
[0] https://www.bloomberg.com/features/2025-bottlenecks-transfor...