A super simplified explanation:

There are a few orgs who have a claim to the rights. By going through their records/finances, it would not be hard to figure out who ACTUALLY owns that slip of paper and deserves what percentage of the royalties. But said orgs have no incentive to open up their books to an audit and no desire to potentially give money to one of the other orgs that they actively dislike.

And it gets even messier because the people who have the hard drives with the code and assets (assuming they even exist: See Icewind Dale 2) might not be the ones who own the rights to NOLF who might ALSO not be the ones who own the rights to Cate's likeness in media because the early 2000s was around the time we were putting video game characters in maxim and playboy...

So the easy answer is "nobody knows who owns it" rather than "one of these three assholes owns it" considering that GoG et al want to convince said assholes to do them a solid.

Weird. I thought I’d downloaded them a while back. I must be wrong.