I like Singleplayer games... mostly 'cause my friends don't come online much anymore....
But you were saying making something similar to Stanley parable? Maybe it could be a singleplayer/multiplayer where you don't have to have friends to play, but you can have friends though.
I mostly play games solo since I'm too anxious to ask my friends to play something.
And I generally prefer singleplayer games. Fun in them is not dependent on your internet or available friends or the teamwork of your team vs the other team.
Plus, stories in singleplayer games can be really unforgettable and unique, whereas there usually isn't a story in multiplayer games.