[xlr8or]

I think if nothing else the replica market increased the customer base for the current Shelby offerings.
Popularity has a strange way of adding to sales figures. It's the band wagon effect in action here. As the replica's get more popular and sales increase there will be more people moving up to the top line levels such as Shelby and Kirkham.
As stated elsewhere these are just hot rods that look like Cobras and the more popular models of hot rods command higher prices. Look at the 32 Ford Roadster as an example.. It is one of the most popular street rods out there and the "replica" parts tend to cost a 15 30% more then parts for a '34.