“but you still have ESD issues with boards, not just chips”
True. So boards are more sensitive to EMP damage - especially if they are connected to other boards with ribbon cables and power supplies. Definitely vulnerable in that case.
The spectrum of an EMP is up to 1000MHz, but the majority of the energy is concentrated towards the lower end of the spectrum. This is the unclassified version of a “reference pulse”.
This means that longer wavelength energy will not readily couple to short wavelength conductors in the board. there are also polarization issues, and orientation issues. For electrically small devices the field strength (not the same as ESD voltage) even at 50,000 V/m the energy coupled into a stand alone system will be relatively small - perhaps within system tolerances. Damage is certainly possible, but not as likely for systems with electrically long conductors connected to it (power cords, conductive data cables, even ground wires, etc.)
The other thing to keep in mind - to differentiate from ESD - a “ground” in ESD is not necessarily a “ground” for RF/EMP. You can still get an RF shock (and arc across a semiconductor junction) without being specifically grounded. A ground wire can act as an antenna and direct energy INTO a system. This again seems counterintuitive, but it’s one of the joys of EMP/RF assessment.
I tink the concern , and you seem to agree in part with your last two posts, is not the rebuilding of the grid per se, but the rebuilding of individual components of society, component circuit boards
making a generator put out power, that can be done after a while, but you need something to put power too
that means you need to replace components on boards
you need people to troubleshoot those boards
most of them are dead by then