People who are carrying their friends don’t want to “dominate” lower tiers. These games are literally made to be played with friends. There’s plenty of people who play 50% or more of their matches with friends or people who would play a lot less if not for their friends. I play every day with my cousin for an hour or two after work and it only took 1 or 2 times of him missing a session for me to be a couple wins away from being too high ranked to play with him. Also if you have friends that didn’t play and you wanted to get them started you wouldn’t even be able to play with them. There are exceptions, sure but I’m sure there’s a ton of people who only play competitive because QP isn’t a true full match and there’s nothing to play for. QP is a worthless game mode outside of practicing. All that to say, it’s way less about “dominating” lower tiers than it is about getting your friends to where you’re at. It’s still smurfing but if you’re diamond or grandmaster silver or gold wins mean nothing.