It seems pretty simple.

Hangar 9 caters to the ARF crowd. The arf crowd easily falls into the "I want it now" category, and gets bored quickly...demanding new and different toys!

Marketing 101 says to sell, the product must be desired by the consumer. So, to satisfy a customer that gets bored quickly, and "wants it now," they change the product line on what seems to be a regularly rotation!

or so it appears to me.