I personally play multiplayer games that have single player aspect to it like a campaign. I don't think that single player is dying out, I think it will be around forever.
At the stage of my life I enjoy single player games now the reflexs are not as quick as they use to be for multiplayer games. Am more into co op games with friends. But hey everyone has their preferences.
I'v loved single player games in the past, like resident evil, pro soccer and some golf games, yeah golf!! But actually after training a lot thanks to these rocket league tips , I enjoy Rocket League as the best one, so my vote nowadays would be for multiplayer games, as long as you are good on them. Otherwise it would be painful.