"Council of Thieves" was the first Adventure Path for the Pathfinder RPG. There were four published before then: "Rise of the Runelords", "Curse of the Crimson Throne", "Second Darkness", and "Legacy of Fire". TBH, I would be quite surprised if there was a huge demand for a compilation of any of these - while good, none of them quite set the world alight as did "Kingmaker" or "Rise of the Runelords" (or, more specifically, that first adventure, "Burnt Offerings").
I agree, though, that a compilation of "Kingmaker" seems likely in time - perhaps for the 10th anniversary of the AP product?