I'm not sure how the dynamic got started here of tall bikes going cheap, but when I know I'll get 30-40 cents on the dollar if I decide to sell the bike that definitely affects how much I'm willing to pay.

It's different at the co-op where I volunteer. Sometimes we have too many small bikes, sometimes too many big bikes, but it evens out over time and I don't think we really have to discount one size more than others. Which makes sense, because I don't think height distribution has changed that much in the American population over the past 40 years.