The player pool is supposed to be left open to help players find matches faster but I can see how it can get super frustrating super fast.
There was a point a few years ago my buddy and I were top 30, rank 1 elites and while we usually were matching up with other close teams, I don't have enough fingers and toes to count how many silvers and bronze we faced off against too. Heck, there was one instance of us facing off against a team who were down so many points they didn't even have bronze; I want to say it was wood rank or something -- I'll happily add wins to my official stats but it gets to a point where everyone is negatively impacted by this.
Competitive teams can't advance and other teams (i don't care about any perceived "skill"; sometimes people just want to wind down and relax with buddies or maybe something is going on in the background etc.), just get stomped which ruins the whole experience. All players need better tools to help them both stay competitive and get the types of games they want