FYI this is the same writer-clawback legal mechanism currently at the heart of the Friday the 13th court case, and I have a lot of thoughts/news on that I'm gonna post shortly too.
Basically it seems to me Victor Miller, the original writer of the first movie, will prevail in appeals court against Sean Cunningham (director and producer of the first and several other movies in the franchise.) Which means whoever currently has the rights (I think maybe Warner Bros.?) will have to pay Miller a fair cut in order to move forward on production of a new movie -- which I have no doubt they will, and then life will go on as normal (hopefully.) (There's a scenario they skirt around Miller's rights by using elements originating in the second and later movies, like the whole Ruby Slippers/Silver Slippers thing in Wizard of Oz adaptations, but they'd have to retcon or revise at least a little to get Jason working without Crystal Lake, his mother, or even possibly his own name.)