This isn't really news anymore, and it's not exclusive to Microsoft studios. Many games come to mind, notably GTA/RDR off the top of my head (outside the obvious Bethesda titles, since everyone's more focused on them right now). GTA is also extremely close to the ten year mark between titles; RDR2 was eight years. These big, open world games have constantly been getting larger and taking more time to make for ages now.

They get larger, have more features, content and better graphics but they don't seem to be getting any more fun to actually play (to me anyway but that could be 'old' setting in)