It sounds like GoG has figured out the status of the license, that it's basically void since no one owns Empire Interactive's IP anymore.
I agree, they wouldn't be able to sell for profit as it's a breach of the license when the mods are included.
I'll email GoG and see if I can get an answer from of them.

I've queried GoG's legal department.

As to distributions, I think we can still control the 'official' distribution on EECH Central on SimHQ without much trouble. It won't be any different than it is now.
A person could still release something on their own, but it wouldn't have the Forum's oversight.