More than 50% of mobile games involve all players being on the same screen. Why not make a game in which each player is on his own screen?

When you are on the plane, in the car, on holidays with friends or at home, why not play with the person in front of you while still being on your phone. There are plenty of ideas and genres. Any thoughts on this? 50% of mobile games are local multiplayer games in which players are on the same screen. Why not the opposite?