There's a thread on this subject over at the RPF where some very good pics of their production softgoods are shown and the prognosis is NOT GOOD. Their fabric choices are so far from the originals as to be laughable. I'm sure it's like Nol stated in his post. It all comes down to pricing. Sure, they could make a screen accurate version of any costume but after they've paid their licensing fees to LFL, advertising budgets, and the overhead any company incurs they still wanna walk away with a profit, as they should. Trouble is, if they spend the money to make the suit accurately, their prices will be very high. Too high for the general public, the people who they believe make up their potential customer base.
Besides, I kinda like the fact that "the good stuff" is made and circulated off the grid.