Worse, a lot of the hardware at that level (those big transformers and the like) are not really kept in surplus and are effectively manufactured to order and sourced outside of the United States. And while that's not a problem for countries that are more modernized, if you took down the grid in the United States the economic and food supply implications would be a global issue.
Similarly, if anything ever happened to GPS the logistics and agricultural industries would topple as they are so incredibly dependent on GPS now it's terrifying.
There have been attempts to modernize it and a plethora of articles exist on the subject, here is a semi-decent one Forbes ran earlier this year
https://www.forbes.com/sites/davidblackmon/2019/07/12/modern...