As massive as the God of War is, I still think The Last of Us will be the most pivotal franchise for Sony going forward, considering it could see major success in a variety of mediums: single player, television, multiplayer/live service.
God of War could be a popular adaptation in television/movies, but I can't imagine a multiplayer spin off would come close to the potential of a high quality, live service, TLOU game, when it comes to MTX/MAU/revenue.