Split screen multiplayer evaporated for many reasons. Besides business it's also technology.

I'm not sure you'll find a single indie split screen multiplayer game that uses a modern, queued graphics pipeline (Unity HDRP or Unreal 4+). Even among big commercial games, Fortnite notably supports 2 player split screen, but Rocket League, Borderlands and Gears of War are all Unreal 3 I think.