>>536158249
MMOs have this interesting quality that they're perpetuated by two things.
>Social Simulation
>Sunk Cost

The first is the main thing that draws in new players and holds them, and helps retain players who don't care as much about the second.

But social crowds snowball in both directions. Once your friends disappear, it's less fun, so you quit too, then your remaining friend quit, because their friends are gone, etc.