The long story.
The only problem is that in order for a game that massively relies on multiplayer to really take off, it needs to have many players, and in order to have many players, the game really needs to take off.
The only solution that I am aware that is the best of both worlds is to add multiplayer content, that is also enjoyable if one was to play by themselves instead of with friends.
Which brings me to the actual…
…Reason I have for posting this and that is to ask the community for some game ideas that would work both in a single player game and a multiplayer game.