This "myth" isn't a myth. Most games aren't the "digital key only" style of discs, like how Nintendo has game cards that are just entitlements now, but game companies took huge advantage of the fact that updates are expected, and the game shipped on disk on release day is almost always unfinished and patched with day one updates. The disk image is submitted for manufacture well before the game actually hits the release date.

This goes all the way to things like a version of Tony Hawk skateboarding that only had like one map on the disc itself.

I was thinking mostly about updates. The version of Cyberpunk on the initial disk release for the Play Station was pretty bad but downloaded updates fixed it.

AFAIK, the PS2 didn't download patches or updates for games. If you have the disk, you can play the same game that you did 20 years ago.

Right up until Sony's servers stop shut down.