I wouldn't call the trend towards playing competitively elitist, collapse. Just like with real-life sports and games, where there are better ways and worse ways to win the competition, there are also better and worse ways to win a Pokemon battle. The strategists over at Smogon are simply the people who've done enough playtesting to figure out which ways of playing are better for wins and which are worse. Since Pokemon battles are highly contingent on math for their outcomes, the better ways to play to win are going to be far more precise, in fact, than they would be in real-life sports. So at least as far as just being a competitive player goes, there's nothing elitist about knowing what works and what doesn't.
Though I will say that, far too often, better knowledge comes with an assortment of particular character flaws, which include: arrogance, condescension, mockery, self-righteousness, overconfidence, and indeed elitism, to name a few. It's something all people struggle with, though, not just Pokemon players. *shrug*
Kind of summed it all up there.
If by Elitism you mean people who just know more about the game, the mechanics, Type Matchups, movesets, EVs and IVs, locations, etc. better than most, then yes. That is and has been present from the beginning of Pokemon; people that knew that Golbat was the best Pokemon if you wanted (I think it was) Critical Hits because that was based off of Speed in Red and Blue, people that knew the difference between Special and Physical in Ruby/Sapphire, and just people that knew that the Stats meant anything in any of the games. If by elitist you meant knowledgeable, then yes, it is and has been present.
But I don't think it's fair to think that these people who are knowledgeable are wrong, or are "too into" Pokemon. I personally pick up knowledge as I encounter it. I just don't forget it, so I am pretty close to being an elitist, but that doesn't mean that you should tell me "hey, chill the eff out. It's just a game." Sure, it is, but I mean, it's
my game. It's the game I'm good at. Don't tell me that I'm "too into" it just because I know more about it than you do.
But if by elitist you mean the jerks that go running around, calling people "noobs" and generally just insult and look down on anyone who they deem to be not of their standards, then that is also present and has been for the longest time.
Only thing is, it is not a right reserved only for those who are knowledgeable of Pokemon. There are many people who are basically "noobs" but feel like they are the best and insult or look down upon others. Not only knowledgeable people in the game do this (although a fair amount do). With knowledge often comes arrogance but sometimes, just feeling like you are knowledgeable makes you become arrogant. And some people are just naturally arrogant; they don't need to know anything to become jerks.
But I could say this about sports teams, study groups, church groups, co-workers, any group or crowd of human beings. Arrogance seems to be something that mankind cannot get away from and there is
always that guy or group that just stands above the others.
It's not just Pokemon, or metal archives, or Sonic/DBZ.
But that's if by elitist you meant the second one. If you meant the first one well, yeah. It's been there. Some people like the game more than you, or prefer to be knowledgeable. It's their right and shouldn't be looked down upon. And that's the wonder that is Pokemon; you have the option to do whatever you want in Pokemon. You can be Mr. Big Shot Pokemon League Legend and have a 100-0 win record or just be super knowledgeable on all things Competitive, or you can be that casual player that all around just loves Pokemon. And you're not really wrong either way.