I found a fun article explaining some of what happened with the 1967 Leaf Start Trek cards and why they are so hard to find.
Article title: There's a good reason the first Star Trek trading cards are so rare — and so weird.
Click the picture below for the link:
A PSA graded wax pack was auctioned by Mile High Card Company in 2017.
Click the picture below for the link:
I'm not so sure I buy the story of limited distribution in "area states like Illinois and Ohio". It appears that "Star Trek" was Leaf's last trading card release for several years, but right before "Star Trek", Leaf successfully distributed "Good Guys & Bad Guys", "Munsters" and "Carrison's Gorillas", and as far as I know, known of those had "limited distribution", so why would they have issues with "Star Trek"? I find it more believable there were rights issues and the distribution was curtailed. Where did the author get his info about distribution?