Carl on 24 August 2017
Because it doesn't have to be on Xbox One.
Age of Empires has a long, healthy history on PC. Relic Entertainment has a long, healthy history on PC and have specialized in developing RTS games for PC for over 10 Years. The current Age of Empires and RTS fanbase is thoroughly embedded in the PC market.
Furthermore, there's no real guarantee the extra money, time and effort spent on developing a version of the game that could work on Xbox One, would be worth the extra money, time and effort. Anyone really interested in playing an Age of Empires game in 2017 is going to buy it on PC, and is already playing multiple other RTS games on PC.
