There's no point in building an immersive game in AR. The whole point of games is so that the players can escape reality for a brief moment and enjoy.

Of course there will be niche games that let you interact with the real world, just like how Nintendo Wii discovered its niche, but most likely games will take place in VR.

Another reason AR doesn't make sense for a game: People don't want to walk around when they want to play games. VR lets you walk around without you actually walking around. All you need to do is twiddle your fingers around. Nobody wants to pour in work just to play games (With exception of the niche games like Nintendo Wii types as I mentioned above)