• Just because something happened first, that doesn't make subsequent additions/mutations/directions a gimmick. The first movies were silent, that doesn't make dialog fucking gimmicky. 
• A gimmick is a quirky feature designed to stand out from the competition. Since all home console games moved toward single-player experiences out of necessity, they weren't putting in something weird to stand out. It wasn't a gimmick -- it was an industry-wide shift to meet demand and work with what systems were capable of at the time. 
• By the logic presented in the argument, anything designed for commercial purposes is a gimmick. That means everything that exists to be sold, apparently, is a gimmick. This is obviously not true, because it's fucking demented. 
• Toddlers? Toddlers sit around in their own shit and think ghosts are real. Are we really using them to demonstrate how the world should work?
• Toddlers?
• Fucking toddlers?
• Really?

In his defense, Antonsson did say that single-player games could still exist (we have his permission, thank Christ) but that they have to be designed well and appeal to gamers ... which ... should be true of all games, surely? He also said single-player games shouldn't exist just because they're supposed to be single-player experiences, even though he said that they're supposed to be multiplayer experiences, which I guess means multiplayer games don't have to be good ... is his ... what he means to say there ... is ... huh?

Owls? Why are there owls in my shoes?

Trying to understand that guy's point is making me go peculiar. 

Videogames is owls.