Ed - I'm sure you are correct about many original cutouts. No doubt many were just burned up.
But in my limited experience, I have found quite a few that just needed cleaning and adjustment. This example I just did tonight.
First I tested it to see if it was functional. It was, but the points didn't close until about 9 volts. This cutout was virgin, never been apart. I carefully cut and split the spot welds, then pried the cover off as I described above. I found the points had some pitting, but not bad. They were also mis-aligned, the gap was too large and the air gap was too large. I gently dressed the points and reassembled, setting the closed air gap at about .010" and point gap at about .020" I tested it again and closure voltage dropped to about 8 volts - better, but still too high. So I lightened the spring tension a little and retested - the points closed at about 6-1/4 volts - perfect.
I know they cannot all be saved, but I think many can. It just takes a little effort.
Steve