To what state has gaming dwindled?

Why is it every game developed is rated on its multiplayer capacity, and why is it every game which is obviously meant to be a real game rather than a brainless net-arena is met with bewildered surprise? “It doesn’t have a multiplayer option, but don’t worry — it doesn’t need it. It holds up as a single-player game.” Bring back the days when multiplayer gaming was constrained to a subservient second controller and the quality of a game in and of itself was what mattered.