I wanted to give this guy the benefit of the doubt and say that he's talking about single player only games, which rules out a lot of the games mentioned here - although ones like Skyrim are still notable successes, but then I realized that doesn't make sense.
Blizzard doesn't make single player only games. I'm not sure they've ever made a single player only game. He's welcome to his opinion, but that's all it is, it has no real bearing on anything else. Blizzard is focused on multiplayer (or a significant multiplayer component), and wouldn't likely be changing that regardless of the atatus of AAA single player games.