I apologize for re-hashing such a controversial and beaten horse topic, but I was hoping to get some clear, concise options (instead of the back and forth quoting and bickering) as to why GOG is unable to release several of EA's game expansions. (Unfortunately, I gather this will probably descend into arguments.)

I assume one of the main possibilities is that the expansion(s) were developed with other studios outside of EA's control, who haven't given permission to use all or part of the content necessary to release the expansion(s). (It's kinda strange because one would think that those companies would want SOME share of the "pie," instead of none, but meh...)

What other potential reasons are there?

It's actually likely to be almost purely that. If the studio has dissolved or been absorbed by another company than EA it's a legal headache. Another apparent problem is that theres some debate over what GOGs contract allows them to release.

If the first 1000 times you don't succeed, try and try again?

Because you touch yourself at night?

Actually, that's what caused the dinosaurs to go extinct. Thanks.

None of the reasons that have been discussed in this thread or other threads about this topic.

So you legitimately know why they can't release? (Obviously, I don't expect the reason.)

I'm not positive but I have strong support towards several reasons.

The margins of which this forum is too narrow to contain.... *shifty eyes*

Strictly speaking the dinosaurs had the only authorized copy.

Back on track, the expansions aren't necessarily owned by the party that made the original games. Hellfire for instance is owned by Sierra and Sierra is now owned by Activision Blizzard, but probably not the same division as Blizzard owner of Diablo. So, even if by some miracle they were to sign Blizzard you wouldn't likely get the expac. Although it's almost certain you wouldn't as Blizzard doesn't recognize that the expac even exists.

After all this time no official comment from GOG about this?

Which incidentally is also the most likeliest reason why System Shock 1/2 and Thief aren't on GOG.

Likely because they're still in the process of legal and contractual negotiations to secure the rights, and legally they're not in a position to make a concrete statement unless they've arrived at a firm outcome.

Just out of curiosity. Syndicate wasn't released together with the first batch of EA titles because of one of these obscure legal reasons. Now that these problems have been apparently sorted out, has GOG explained what was the nature of the problem? or is this legal stuff so arcane that can't be discussed even when solved?

Someone pointed out in the Syndicate announcement thread that the Syndicate expansion was developed in-house by Bullfrog, the same developer that made the main game. So the "external studios" explanation would not apply at least in that case.