Sometimes licenses get in the way, it’s possible they bought em engine or tech from a 3rd party and don’t have the legal standing (or don’t know if they do or not) to release the source.
Fallout source is gone too. There was just no reliable way to store source code back then, a lot of times it was just one of the developers that had it sitting in a desk drawer.
Subnautica's Original Creators Have Been Removed From Unknown Worlds "Effective Immediately", As Krafton Makes Concerning Leadership Changes (www.thegamer.com) angielski
Kerbal Space Program 2 vibes... I'm suddenly less optimistic on subnautica 2.
Stardew Valley creator says he might make Stardew Valley 2 (www.tweaktown.com) angielski
The creator of Stardew Valley has said that he might make Stardew Valley 2, but he really enjoys just adding ‘more stuff to Stardew Valley.’
EA has open sourced a bunch of old Command & Conquer games (github.com) angielski
I’m not well versed in C&C, but it’s always good to see more games open sourced.