Since practically the dawn of the video game console, game makers have tried to set their systems apart with games made in-house by first-party studios or from wholly owned second-party subsidiaries. But the idea of large, independent third-party developers releasing games exclusively on one console or the other has risen and fallen in popularity over gaming's short history.
When a few Atari programmers split off to form Activision in 1979, they weren't eager to tie themselves exclusively to …