I don't even think it's that. I think the demand for Infinite content will dry up pretty quickly unless the Multiplayer takes off on PC. I say that because a lot of the Halo players who left the Halo scene starting with Reach and for that matter the Xbox ecosystem went over to pc. Pretty much 75% of the EU competitive scene from the H2/H3 days are on PC now.
Also based on everything we have heard about its development, 343s history with Halo and the gameplay reveal inspire zero confidence that their is even the resemblance of aplan in place. Imo it's only chance of hitting it big is a successful BR mode.
PC and xbox is crossplay, this will help it. It all comes down to the engine and the initial map selection imo, needs to really nail it. Once a good foundation is in place it will only grow imo