While technically the xbone is a weaker console (and is inferior to many gaming PCs), because it is a known configuration the system specific code, e.g. graphics, can be more easily optimised for the console. While any new gaming PC will pretty much always have far superior graphics and processing capability compared to a current gaming console, the additional complexity of writing stable but efficient code for an innumerable set of system hardware configurations adds a lot of extra work. Porting a title from PC to xbone is usually a little easier than porting to PS4 because they are more similar architecturally and while there are quite a few cross platform libraries available, there's always annoying bugs or capabilities differences in one but not another.