Klikidiklik: You offer a 50% discount for this game. But on Amazon you get the game for 9,99 Euro or as Key for 6,91 Euro. Why is this game so expensive on GOG?
If you have read up on what the Homeworld Remastered collection comes with, you might have a better idea.
For one thing, many older games of Homeworld's quality would still probably be AT LEAST $10 on GOG, so if it were just Homeworld 1 and Homeworld 2, it'd likely be around the $20 range together. That covers the current sale cost, just about.
But this doesn't just include the classic versions of both of those games, it also features the Remastered versions of both Homeworld 1 and 2 rebuilt in an upgraded version of Homeworld 2's engine for modern systems. Along with that comes new voice work from the original voice actors, new art (as in ship models, skymaps, textures, etc.), new gameplay mechanics (the huge patch that just came out revamped Remastered's gameplay quite a bit, and yays, ballistics!), multiplayer for modern gaming networks (which also features multiplayer between the factions of the original game and the sequel together), completely redone soundtrack, and etc.
So if you were expecting to pay $5 for a more recent classic, that was unlikely from the start. These aren't potentially used discs or copies of the game that likely require a ton of work to get operating on current PCs from the start.
The only thing really missing, at this point, is Homeworld: Cataclysm, which all I can hope for is it getting rebuilt from scratch or the code popping up at some point.