Posted By:
boxingcardmanbecause of the wide disparity in value between postwar cards (especially post 1980) and the value of prewar cards. I once sold something like 10,000 crappy modern cards at a garage sale for $20, so I've definitely sold more cards than I own, but the measure is meaningless as a result of the disparity in values. A more salient question would be whether you've sold more in value than you currently own.
Edited to say: and to that I can say "no" but probably not by a lot since so many of the cards I sold cheap in the old days are worth so much now [insert milk spilling and crying sounds here].