Also, Atari's official announcement on January 23 (again, easily searchable on the GOG forum I mentioned and Atari's official subreddit), stated that the studio's own development tools, don't allow for this content to be efficiently replatformed to GOG and VCS.

There could be some credence in this statement, at least in regards to Digital Eclipse's previous approach in repackaging the Disney Collection on GOG, where, instead of adding the additional game, that Steam users got as an update (?), Digital Eclipse replaced the original collection with the full version that Steam users have.

Which begs the question, why not re-release Atari 50 on GOG as the 'Expanded Edition'?
Again, this could be related to my previous theories.

For everyone else: search Atari's statement on their VCS subreddit.

If other users on here can't find the official Atari announcement, then of course I will send this.

If one reads my posts, though they are rather lengthy, a goal of mine is to help raise awareness of the endemic issues I have mentioned regarding longing standing update issues on GOG, and part of my drive - which, concerns all of us, as consumers, is to encourage a proactive approach in researching pertinent information.

Unfortunately, some users seem to simply expect information handed to them on a silver platter - and when, instead, a proactive approach is suggested, they seem offended by this, to the extent of outright dismissal of the relevant channels I tried to provide. For example, implying that I suggested to 'blindly trust ' Reddit. How can you 'blindly' trust Atari's official subreddit? Unless this user was unaware of Atari having their own subreddit in the first place. Again, awareness, or lack of.

Unfortunately, when these requests - for easily obtainable information - are not acceded to, the forum posting etiquette card is waved, repeatedly.
Again, context is key to understanding meaning, and my post regarding Atari's announcement, wasn't me 'claiming news' - this is not 'news'. This announcement has been in the public domain an entire month since this forum was created by this very user.
The point to my post, was rather, quoting my message to GOG Support, in detailing a possible solution to the issue of missing DLC.

Again, I have made significant contributions to this and the 'Wider World of Atari' forum and I hope to continue to do so.

If they had released the dlcs on Gog at the same time as any other digital store front then the sales of the dlc wouldn't affect whether or not the dlcs would be added here because they'd already be here. Now I'm not a game dev and haven't ever released a game on a digital store so I could be way off but it seems to me that it would be as easy as adding the dlc game files to the stores backend as dlc for this game and setting a time of release and after the owners of the digital storefront approve the submission it would automatically release at the desired time and we'd have the dlcs. They're already completely finished being made and sold elsewhere so no dev time would be needed for the dlcs themselves.. I guess I just don't understand why they can't do something that in my eyes should only take 5 minutes to an hour. (depending on how fast the storefront approves the submission).