I think someone above said pretty much how I feel and that's, if you have three different highly talented studios, why make the game go in the same direction just further a long the time line?
Now would be perfect time, especially with it being Infinity Wards year to try something. I don't think ''well, if you don't want to play a futuristic call of duty, you can just play the COD 4 remaster!'' Is a good retort especially if they're not going to sell that thing sepreatly. I'd be interested to see what the multiplayer numbers would be like after a month or two after release if they did sell it as a standalone. Wether it's just people's nostalgia at this point for Call of Duty 4.
Plus, just in my opinion, Battlefield is at least trying to experiment. I mean I don't really care for a world war 1 setting but at least DICE at least realised that they needed to do something other than Battlefield 5... Still, why a Bad Company 3 hasn't been made yet is really beyond me?