I think Microsoft's problem is that when something it big they keep releasing something every year (on top of that broken/disappointing products), Halo 5 was the best response to MCC in that it worked and was great (imo) but Halo Wars 2 next year... what in 2017? Then presumably Halo 6 in 2018... it ends up being too much.
I dont particularly want to get into a "MS does this, Sony does this" scenario because it seems like a silly argument but its not like Sony have studios work on franchises for long periods of time. I don't see a big issue with having a Halo or Gears studios personally, they have plenty of other new IPs coming, the problem is the constant flow of titles in that time, Fable is also guilty of that although Lionhead were on a new IP, we haven't seen it yet, though.