I agree. Actually, aside from HW THunt's and JL White Lightnings, non of the other manufacturers chase cars ever seem to go for big bucks. I've got two of the Maisto Playerz Ace chace cars, 1 of 2500 (far fewer the a TH). The MB New Super Fast chase cars are either 5000 or 7500 depending on the release. Other than the '04 C6 Vette (I forget whether it's the blue or black one I still need), none of these command any kind of money.
Oddly enough, sometimes they're easier to find than the TH or WL. I'm just happy to find a "chase" car period.