People usually hate the idea of balancing around pro play because "muh .000001% of the playerbase", but they fail to put much more thought into it than that. I am going to list a handful of reasons why balancing around pro play is a must for riot.
>Esports is a cash cow.
Everyone already knows this, but esports gets riot loads of money. It's in riot's best interests to balance pro play to keep it interesting for pro players and those watching. Seeing Sion/Aatrox/Urgot in the top lane every single game is boring af and will bleed viewers away.
>Balancing around pro play doesn't give much incentive to get better at the game.
What's the point of learning how to face Master Yi, Garen, and other champions that tend to stomp in low elo games if riot is just going to nerf them into irrelevance? What's the point of climbing in elo if the viable champion pool grows smaller and smaller? Right now we already have an issue where once you start getting to diamond+ champion pool starts to shrink because champions are no longer viable. Now imagine if this problem is magnified to an even greater level.
Although high elo is about 2% of the playerbase, it makes up the vast majority of content creators for the game. I'm sure you can see why restricting champion pools (makes the game more boring) isn't a good idea. Content creators bring in new people and keep them playing.
>Pro play still translates into your games
Strategies used in pro play are usually difficult to implement into pro-play because of a lack of communication, but that doesn't mean everything in pro play is irrelevant. A specific example will make this make more sense.
Back when Azir was 100% pick/ban in LCS in season 5/6, occasionally you would find a good one in one of your silver/gold games. Now if pro players, the best at playing LoL, struggle to face an Azir, what chance does a group of uncoordinated and unskilled players have?
EDIT: Put very concisely and very simply.
> I'll throw in my two cents. If something is overperforming at low elo, it could be that it's a novel strategy/design, or difficult to play around, but perfectly balanced. If something overperforms at high elo, there just **isn't** sufficient counterplay to it regardless of skill level.
> Put more concisely, balancing around high elo removes many confounding factors when assessing pure kit strength.
>People still play tournaments in low elo and pro play strats still apply
This was something I didn't think about super hard until I recently joined a few tournaments, but the strategies and gameplay that you see in LCK, LEC, etc. isn't that far away from you. If you can find some sort of 5v5 tournament to join (or if clash ever works properly) then you'll understand how disgusting and how useless some champions are.
Sejuani might be trash in solo Q, but suddenly you face one in a coordinated environment and you understand why she's constantly getting nerfed.
Sion might be "meh" right now, but when you see a 6k hp sion running at you with his whole team behind you, you'll understand why he's picked so frequently.
Orianna is not a good mid laner right now, but she stomps coordinated games because of her insane teamfight.
Yi is basically freelo below gold, but useless when facing coordinated comps with 2 tanks and enough CC to keep you locked down for 4 seconds.
>Finally, it just doesn't make sense to balance around people who don't know how to play the game
The whole point of games like league is to get better at them and beat other people with your skill. Why should we balance around the lowest common denominator?
Now I get it, no one wants to be DOTA2 and have heroes that are winning 60% of games and being picked in 40% of them, but no one wants LCS to be limited to 20 champions either. Finding a correct balance is key, which I think riot is doing an OK job at, but should focus more around pro play than they currently are because of the reasons I've stated above.
I didn't do much research on the current meta in this post, so if a champion is stronger/weaker at a certain elo than I said they are, just roll with it. The point isn't to talk about champions specifically, but talk about the game as a whole.