I’m not sure what you’re saying here … 1.6 is an upcoming full game update for Stardew that will add even more content, which he was simultaneously developing with Haunted Chocolatier. They are a very small independent operation, and game development takes more time the fewer employees you have. The fact that they have continued improving the game for 7 years adding free content at the original price point is actually quite remarkable.
The 1.6 update addresses the ability to create add-ons (mods) more easily, which will aid efforts in the modding community to create things like Expanded with less fussing about in third party programs and tools which currently allow them to work.
Spoiler: 1.6 sneak peek from ConcernedApe’s Twitter posted Sept. 27, 2023