The root cause is that Xbox management has always lacked a clear vision.
You can see this from the late 360 era onwards, when it was clear the market was shifting away from the things they had built their successes on earlier in the gen and yet they did nothing to adjust. They assumed annual Halo, Gears and Forza were always going to be enough to support their core, and the route to the broader market was via motion controlled family games and plastic-instrument based music titles.
When all these things fell off... they stubbornly stuck with this approach in terms of content as they were at that stage balls-deep into their masterplan to make the Xbox One this monetizable universal media bulwark. Hence the whole TV TV TV push.
Unfortunately for them, this failed on every level as a resurgent Sony went on a charm offensive to court back core gamers they had lost in the PS3 era.
Everything that's happened since has been a consequence of that, mainly because MS have never really cared about or understood gaming, they just looked upon it jealously as another revenue stream that could be used as a tentpole around which to build a comprehensive consumer entertainment offer.
The methods and approach have changed over the years, but that fundamental flawed intent has been a constant. Its all just been a means to a larger end, which is why they've pivoted so hard and often and yet very little has actually changed.