"To which I add the differences between the average tube-based Euro radio made between say.... 1950 and 1980, and the average American tube radio of the same era. "

But Euro is the bomb !

Look at new cars, want an aftermarket radio ? In the old days it was two nuts in front and a bolt in the back, now you have to cut the HVAC controls off of it, get a kit from Crutchfield and be handy enough to build the damn thing.