From 1968-1989 there were only two major hockey card issues each year - a Topps issue marketed to our American friends and an O-Pee-Chee set distributed across Canada. To Canadian collectors there is no competition - because of familiarity and nostalgia the O-Pee-Chee issues reign supreme. Book values (and actual selling values) of the O-Pee-Chee are often many multiples of the very similar Topps issues.
Although no definitive print run numbers are known I would suspect that selling price of O-Pee-Chee sets is a function of demand alone not scarcity. O-Pee-Chee singles abound (really high end singles are another story...) when compared to their Topps counterparts. I would suspect that the print run of O-Pee-Chee cards (to serve the hockey made markets in Canada) were many times that of the Topps issue. In fact filling wantlists for Topps sets is a difficult process especially for sets from the late sixties and seventies. When found, however, Topps cards tend to be better condition - a product of better cardstock and quality control.
I suspect that this relative scarcity of Topps hockey (in Canada at least) will ultimately bode well for the value of of those Topps sets from 20-30 years ago as collectors finish their O-Pee-Chee runs and want to move on to the next challenge.
This situation is the exact opposite of the situation for baseball collectors. Well-heeled baseball collectors in the US are finally realizing that there is a "parallel" issue for each of their Topps baseball sets from 1965 on. And indeed vintage O-Pee-Chee baseball sets provide a distinct challenge both north and south of the border. Till next time.