This has been the case for the entire history of philosophy. Any time a philosophical question received a definitive answer, it became a separate field unto it

This has been the case for the entire history of philosophy. Any time a philosophical question received a definitive answer, it became a separate field unto itself. So it was with mathematics, science, and law. Philosophers continue to debate these fields (I’m studying philosophy of mathematics right now) but it has little bearing on actual practice. I happen to be partial to the Wittgensteinian view that philosophy is primarily therapeutic, but I won’t rule out the possibility of philosophers creating new disciplines in the future. John Rawls had some very nice ideas about justice but by no means did he settle the debate. For one thing, he was a utopian, opposed to property rights. That is unrealistic, unless you’re talking about some hypothetical post-human society. To create any workable theory of justice, I think you should start with the basic assumption that you’re dealing with human beings who naturally incline towards competition and status-seeking. Envisioning a society without some of the traits of human nature is the epitome of Utopianism. You might be able to engineer these traits out of human beings but then you’re dealing with a post-human world.