What is the legal difference between owning digital and physical media?

Sony is Sony is about to delete Mythbusters, Naked and Afraid, and tons of other Discovery shows from PlayStation users’ libraries even if they already “purchased” them.

So, if you bought a DVD licensed by Sony, can they now legally enter your house and take your DVD?

Or can Sony have some sort of DRM that prevents the DVD from playing when Sony loses the license agreement?

I'm just trying to reconcile how digital purchases can be subject to license terms changes, while a DVD apparently can't be.