Both of these cards are checklists from 1966, both produced by OPC (despite the fact that both say “Topps” on them). One is a first-series baseball checklist, the other is first-series hockey. I don’t have production numbers, but based on experience, the hockey checklist is far more readily available than the baseball one. It’s not easy to find nice-quality 1966 OPC baseball whereas 1966-67 hockey, though extremely condition-sensitive due to the stupid brown borders, is comparably common.
The baseball checklist runs about $10 in EX-MT/NRMT unmarked condition. Hockey? I’ve seen decent-ish marked 1966 checklists drawing $25 and if you want a solid unmarked one? Multiply that by 10.
(So yes, the mashed-up card at right outdraws the quite nice one at left.)
It’s not just this set. All 1960’s checklists run at least $100 and the worst of the lot is the 1971-72 first-series OPC, which I’ve seen go for as much as $500. (Mine has a hidden crease, and no, I’m not going to bother upgrading it.) In most OPC sets prior to about 1982, the checklists are in the top 10 cards in value, and in the 1960s, they’re usually in the top 5. (One of the great joys of collecting hockey prior to 1961-62 is that there are no checklists to worry about.)
So why is it?
I put the question to the owner of my newfound LCS (as I was spending $10 on a 1979-80 OPC checklist that’s not quite as good as the ’66 baseball above) and he said that baseball checklists simply didn’t seem to be used as often. His guess as to the reason why was that baseball sets were so much larger and issued in so many more series that kids just didn’t bother. Hockey sets were more achievable, so kids tracked their progress more.
Can’t prove it either way, but it’s an interesting theory.