I met a woman two weeks ago who autocrosses an S2000.
I think the reason there are not many S's are multiple. One, I just don't remember Honda marketing the car all that much. Mazda markets the crap out of Miata's and RX-8's and the sales numbers show for it. Two, the car is not exactly inexpensive. Three, the lack of an automatic will definitely keep many from buying it but getting an automatic to work with an 8 or 9,000 rpm motor is no trivial matter. But I think number one is the lack of marketing. Better mouse traps do not sell themselves no matter how good the mouse trap.