There is a useful service Pantone is providing: when I want a physical thing to be a certain color, I can buy that color ink from them to get it consistently. But once I've applied the ink to the thing in question, it's mine like that forever. Imagine that Pantone demanded all of their customers to pay them protection money every month, or they'd send their goons to spray-paint black over everything you ever used their inks on. That'd obviously be completely unacceptable in the physical world, so why is it acceptable for them to do it to your .psd files?