One of the main problems with single-player video games is that a lot of people work alone and don't want to spend their free time doing something that feels kind of like work, but doesn't seem to offer much in return. They'd rather spend their time socializing or doing something that will improve them in an obvious way. A personal anecdote - I loved single-player video games until I was 18, but I stopped cold at tha…
I play some multiplayer stuff but I'm like 90% a single player gamer.
I find other people (like public servers in Battlefield or the screaming/hacking teenagers in GTA Online) ruin games more often than make them better.