AFAICT, you're right.

A standalone offline player that can play Movie A today will be continue to be allowed to play Movie A forever.

Subsequently-purchased movies B, C, and/or D may or may not work (because of shenanigans like key revocations systems), but Movie A still plays fine even after these later titles have been introduced.

It's ugly, but it's not quite a brick.

The ugly part is shaped like this: A person buys a new movie and it doesn't work. They can't return the movie to the store because it's been opened, so now they're left with a disc they can't use and with less money than they had before. (Solutions include figuring out how to update the player's firmware if it's still supported, spending more money on a newer player, or becoming an Amish leatherworker and forgetting about all of this nonsense for the rest of their days.)