When did gaming become about shooters and playing online?

All of a sudden it seems like all people care about are shooter games and if you don't play a shooter online you aren't a "hardcore" or real gamer. I love Mario, RPG's, adventure games, puzzle games...all kind of stuff more then I like shooters and I never play online. Does that mean I'm not a "real" gamer? Where did this elitist way of thinking come from? I grew up in the N64/PS1 era of gaming and it wasnt like this!When did gaming become about shooters and playing online?
Because people eventually get tired of single player and want to play against each other.

Also,gaming is also about strategy games.

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