My RBG group with 5x 0 rated players, and enemy team has:
1847
1740
1705
1679
1669
1668
1423
Is it really this dead?
Pretty easy to get 1800 just by doing yolos for cap
Were these initial (placement) games where you still don’t lose CR?
If so, you can get put in some higher MMR games just to see how you do. Especially if you have a win streak. Even a short win streak will put you in a much higher MMR game than your team might be ready for.
They do this so strong teams climb out of the bottom quickly.
Look at your team’s MMR value, however, relative to your team’s CRs. The delta is high just because it is naturally dead at higher MMR. CR doesn’t really mean much for matchmaking unless the CRs and personal MMRs are close after playing all of those placement games.
The OP is looking at CRs and thinking something is wrong when that is just the way the system has already been working.
I’m just answering yes to rbgs being dead, which they are
Three games in and facing top 3 teams, lose and face the team we faced two games before 
Yes, your screenshot shows that it looks dead at higher MMR, but the OP’s screenshot isn’t really something that out of the ordinary is all I am saying.