This is something people have been saying forever as well, and I'm pretty sure it's largely a myth.
It's something people have been saying about Disneyland in particular, that the annual passes will see changes in price and conditions to reduce the crowds.
There is a little bit of truth to it. In recent years Disneyland saw certain passes not be sold for a period, and block out dates for Star Wars next year have come into play.
Generally however, Disney wants their parks to be packed.
As guests, we like smaller crowds. As a business, Disney wants more people. And who can blame them, for all the complaints about crowds, it hasn't deterred people from visiting.
As the saying goes, "Disneyland, no one goes there anymore, it's too crowded".