Xbox Wont Allow Series X Exclusives

Despite several games having issues with the Series S such as Baldur's Gate 3 and Black Myth Wukong. Phil Spencer says Xbox has no plans to reverse their decision that all games for Xbox must work on the Series S and Series X. Spencer claims the idea will help companies who are developing games for handhelds with lower powered specs. Could Xbox be hinting that their rumored future handheld will have a similar requirement?