Manufacturers wont know there is a demand for something unless you tell them, and ask them for products.
for example, i am after some coilovers, but i dont fancy anything that is currently available. So a few emails later and i have the UK importer of Ohlins talking to the factory in Sweden to check the options.
You want something different or new, you cant expect it to just appear one day. People need to know what your after, and see if its a viable product to develop.
And as mentioned by many, thier cars are pretty new, still under warranty etc, so are less likely to want to spend big, or mod big.