[Exhibitman]

It is really hard to label cards from the 1970s as junk wax from 40 years later. In the 1980s-1990s, there were some definite distinctions I saw when going to hundreds of card shows that might be helpful to the discussion.

IMO, the closest thing to junk era vintage is 1978-1980. Those cards were issued in great abundance and buying back in the day, I recall 1979 Topps wax and three-pack trays available at shows for years after issue, very cheaply. I opened 1979 tray packs for years chasing a Smith RC (stupid move, BTW, worse than drawing to an inside straight). Same with various configurations of 1980. That bears out with the stacks of these cards you can find in high grade at shows in common boxes.

1977 is kind of a transition year. I never saw unopened in the volume that the next few years brought but there was still quite a bit of it.

1974-1976 is the next tier. I really did not see these cards as unopened in any quantity. I understand that there were some big dealers with giant caches of unopened but it wasn't out there like later years.

1973 is another transitional year. It is the last of the series era, though in some areas all 660 cards were issued at once. Still, the high numbers are notably tougher than the rest.

I group 1957-1972 together. Size standardized and high and semi-high series that never made it into every market.