We're already a lot closer to it than you think. Do you know how many modern games don't even fit on the disc in the first place? Or ship incomplete because in order to meet a target release date they have to start pressing discs before 1.0 is actually finished? And what about all the updates and DLC?
In 50 years time, when servers are all gone and you can't redownload the data that wasn't on the disc, do you still own your games?