Azzy
ᚳᚣᚾᛖᚹᚢᛚᚠ (He/Him)
Given that the lion's share of the OSR retroclones are based on B/X, I think that your experience may not be universal.The thing is BX was available in toy stores and all kinds of places. And everyone I knew who played AD&D always said to buy that first. But at least where I was playing AD&D was by far the most popular (we had people playing B/X but way, way more played AD&D that I saw)