I think that part of the problem is that the ZS prices have dropped sufficiently to be within the grasp of the boy racer brigade. There are a minority of cars being bought by enthusiasts such as people here, but the prices are now at the point where people buy them with the view to have some cheap fun and not worry about mainaining the car as they should. Hence, more get crashed, and the premiums go up
As a comparison, I'm paying the same for my ZS 180 as I was for a 240bhp Supra Turbo...