I suspect that anyone that asks nicely and plays by the rules can get a copy of the P96 DDK. (EDIT: I suspect it because that's how I got a copy. It was several years ago, though.) I agree that a closed solution is not ideal, but nothing prevents an enterprising developer from designing a P96 shim driver that allows an open standard to be developed. If the open standard is adopted by enough developers, it provides the impetus to move all systems to the new standard.
