Once a BR has saturated the market, the percentage of new to experienced players starts to drop. I think most players will reach a skill peak and the game starts to get harder faster than they are improving. This can be frustrating, and since newer BRs have a higher percentage of less skill players they feel easier. With no money barrier, the players switch.
I had written some comments similar to what you are saying. Getting into e.g. PUBG right now would be very difficult.
Do any (modern, popular) games implement this kind of matchmaking? I believe there's often a monotonically increasing 'rank' or 'level' displayed to the player, but I'd be surprised if any major games used this kind of score as the sole foundation for matchmaking.