I did a quick search and found a Manchester Evening News article where Brian Phillips was quoted as saying "In my time Djing at The Wheel, imports were becoming more and more prevalent and accounted for around 35 percent of my plays. Soul imports started surfacing in the mid-sixties, turning up in obscure places"
I've no doubt that rarity and exclusivity were irrelevant to many punters at that time, and the same is true today, but it's not surprising to see that that djs were seeking out difficult to obtain records to add freshness and exclusivity to their sets.