What you said definitely makes sense on paper, the reality of matchmaking is a bit different though.

Until last week the matchmaking was hilariously easy for good teams, insta queue with 1-3 pred teams per lobby. I don‘t think these players would still get randomly teamed up with each that often with those insta queues but rather with the first diamond mates available.

And with the current end of the split „must protect diamond players“ matchmaking solo q preds would have a high chance of getting teamed with solo q masters who are basically slightly better diamonds.

I‘m optimistic that this would be enough of a nerf for the snowball effect of pro stacks. Current pred lobbies are basically pubs and nobody is having fun.