Your reasoning seems pretty cogent but there may be fallacies in it after all. You state: "Because the MOST OPTIMAL plastic is the same as RECYCLABLE PLASTIC." Even if this is true it does not logically imply that the plastic that is not most optimal but not that far from it cannot be processed in a way that results in positive gross profit.
Moreover, what matters most in the future is the waste plastics of RKT, including all the raggertail. That is clearly not recyclable sice it exists in vast quantities. This stuff has already been tested on the processor. I take it for granted that this was done before the agreement with RKT was signed. It seems obvious that RKT wanted to make sure that the processor could handle the waste plastic it had before an agreement was entered into.
You do appear to be right. This plastic needed by JBI, if not a unicorn is definitely a very endangered species because of the catch-22 interplay between the DEC permit, JBI's process, and the dynamics of the plastic market.