lets compare League with soccer.

both games you need to score objectives and the one who has the most objectives or the final objective wins in that regard both games are similar. now in soccer you have attackers that are much like big play lee sin they have to be fast agile and "smart" to outclass the defenders now the defenders are usually a bit bigger broader not as quick but can kick the ball hard so that the ball goes away from your goal kinda like imobile champions with superior damage .... wait wut?

there you see even though the professional soccer scene has been around for more then 50 years and will stick around for much longer. why is that?

because each player(champion) gets a fair chance.

if suddenly the defenders from soccer players got a ball and chain around their ankle under the pretense of we need bigger plays. people will stop watching soccer you see a pro sport scene above all needs to be fair, other sports that started favoring specific playstyles and made it less favorable for the other playstyle's people eventually stopped watching/playing said game.

TL;DR riot the imoble low flashy play champions in your league have more then just a ball and chain around their ankle.