Creating a product requires R&D, creating prototypes, setting up and tooling machinery, defining/perfecting a process, trial runs, etc. Sure, large retailers can have some influence on what is manufactured and made available to the market, but our cars are 10 to 20 years old. The demand for aftermarket parts and accessories will eventually plateau and then decline rapidly. Manufacturers know this. They aren't going to waste their time developing and producing products to sell for a very limited amount of time. Apparently there isn't a large enough market demand, or else it would have been done well before now.