Super-limited market, would be my guess.

What's the market for dedicated cross race bikes?
What's the market for single-speed road bikes (of any style)?
What's the intersection of the two?

That said, I really like my San Jose. But, it's not race geometry, and when I bought it, it was relatively inexpensive - steel prices went up and now it's pricey for what it is, IMO. I don't get the fixie crowd's infatuation with track bikes - I think the San Jose makes a much better fun bike.