Sorry to kind of ignore your question, but I think it misses the point.

Even with only the partial game data on the disc, the disc still held the rights to the game. Therefore, the rights were transferrable. That is to say, you could still sell your disc and it would have value to the next owner.

When you are forced to buy the game directly from the PlayStation store, your game license is no longer transferable. You can’t sell your old games, and you can’t buy used games from someone else.