Is it possible for modern games to fit on a disk?
I think it would be an interesting change if brand new games had a hard limit on file size so they can fit on and play from an actual disk.
Absolutely. It just depends a lot on the game of course. A blueray disk can contain over 100 GB. But a game could be split over several disks too. It was rather common to do that with CDs on the original PlayStation.
If they use a good, 12X bluray drive, it will be quicker to install from a disk than to download it unless you’re lucky enough to have a good fiber internet connection. Even then, the servers you download from will often be overloaded and slow on release day.