Curtains and pies take a lot less work to make than new NPCs, dungeons, biomes, bosses, more to explore. A pie is just a slightly different piece of food, a variation on a simple item that's already coded in the game, with a very basic model, something that wouldn't take weeks or months to add. All that other stuff you're asking for? Takes months, minimum.

(Mac shakes his head, grumbles something, and walks away...)