On one of the forums, and industry type (Charlie Vlk?) said that statistically, N scalers buy more rolling stock than their HO counterparts, backing up your assertion. I recall Frank from Intermountain, being really open about sales, and I think their N Scale covered hoppers sold almost as much as their HO versions.
In fact, many of their stuff sold about 66-80% of HO in N, which if its a third the size of HO in particpants, means we buy twice as much!