I can't speak for PPS, but, isn't in their best interest to protect the Copyrights of Bally/Williams? Also isn't it required of them as the rights owners? Again I can't speak for them, just this is my understanding of the how the rights to reproduce Bally/Williams parts works.

I don't think PPS is trying to create some type of monopoly over parts, and it seems that they have worked with other vendors for stuff to be created for games as well. In my opinion I think more parts will probably be produced because of PPS.