I assuming you refer to reclaiming something you got on another platform here.

I kind of understand why they would not want that.

I mean, you essentially gave your money to some other platform, but then you straddle GOG with the operational cost of making your game available for you.

Sure, they don't pay a whole lot for storage (its not as if they keep a separate copy of each game for each user), but they still need to pay for your long term network access to your game.

I must say, from a sustainability perspective, I'm uneasy with the business model of selling something once for a one time fee and then having to make it available online indefinitely (well, until you go bust really). Unless you keep constantly selling a lot of games to people, I don't see how that could work out long term.

I mean, if GOG wasn't around, I'd probably need to pay AWS Glacier ~30$ a month to keep a copy of my games in the cloud, so if one day, GOG came around and said I need to pay a reasonable monthly fee (say 5$ a month which is a lot less than I would pay AWS with a much nicer interface) for continued access to the DRM-free download of games on my account, I'd be ok with it and relieved in a way.

I know its not the expectation most people have, but I think its keeping things honest.

I think there was the option to get Mount and Blade and Warband for free in GOG if you could provide the code that you got when you purchased it at the Taleworlds site.

Thanks for making it clear.

Sorry about that. Thanks for the help!

THanks for the clarification.

Statistics. They know to a very reliable margin that a portion of people will never download a high portion of their catalogue even a single time. It might seem ludicrous to you, but they know full well a large amount of money will be left with them for no real cost. It is (was) essentially the same thing with airlines that they could sell more tickets per plane than there were seats, because statistically a certain proportion of people will for whatever reason miss their ride.

Thinking about it, you're probably right. They probably have gotten enough money from sales to operate for several centuries though of course no company would continue to operate unless they are in the green.

I'm having a small mindset here.

Well, let’s just say it is not that simple ;)
A lot of companies are bleeding money for years, but are seen as huge successes. Uber is a well-known example.

Netflix too as much as people hate to hear that.
Tesla was bleeding a while ago. Can't say about present though.

Is It possible for me to reclaim a SWAT 4 copy I have physically? And if I cant, can I just buy the DLC seperately

The support article you quoted lists eligible games and the one you asked about isn't listed:
Editions sold worldwide:
• S.T.A.L.K.E.R.: Call of Pripyat (GameSpy)
• S.T.A.L.K.E.R.: Shadow of Chernobyl (GameSpy)
• S.T.A.L.K.E.R.: Clear Sky (GameSpy)
• Torchlight (Runicgames.com key)
• Torchlight 2 (Runicgames.com key)
Editions sold in Russian-speaking territories:
• Mount & Blade: Warband (StarForce)
• Mount & Blade: With Fire & Sword (StarForce)
• Eador: Genesis (StarForce)
You can only buy DLC if you own the base game on GOG. If you don't, you can only buy it as a gift (this gives you a key that someone with the base game on GOG can redeem).
In any case, there is no separate DLC available for SWAT 4, only the Gold Edition with the expansion included. It goes on sale for -50% fairly regularly, so consider adding it to your wishlist if you want to be notified when that happens.