Popping off a dozen 0.5Gt nukes in the upper atmosphere will certainly throw a major spanner in the works for much of the industrial world, that is true. The EMP coverage of each such blast is vast, and would make the worst solar flare disruption we’ve seen to date seem like a leisurely stroll in the park.
The problem is: how do you direct such a blow against any of the industrial centres in Central Europe without affecting the corresponding ones on your own side of the Curtain? The distances are very close, and that pulse kind of goes everywhere, without giving a toss about political borders.
So you kind of can’t.
And that’s the point — that kind of a indiscriminate strategic strike is pretty much per definition a MAD doctrine strike. I fry your industry ... sure, I fry my own as well by doing so, but that doesn’t matter, because if I haven’t done it, then you will anyway.
Mutually assured destruction.
And if the war has gone into the MAD stage ... then those EMP strikes and the presumably ensuing industrial collapse is likely to be the least of the problems the people populating the setting will be facing.
Postulating a industrial collapse in the industrial world can be done ... but I can’t see how it could be done that neatly. Logically, it will knock down other domino bricks ... with consequences you might not be all that eager to have in the setting.