There are a number of papers (and I'm very afraid I'm on my phone right now, so I can't cite them. I am sorry for that) which show that things like severe gender imbalance are not self-correcting systems in the case of extreme bias -- you have to push them back closer to 50/50, but then the system will remain balanced.
This makes (to me) intuitive sense -- current staff / managers will tend to employ, and promote, people "like them", creating a self-perpetuating system.
The problem is going to remain - Where do we draw the line? Where does pressure towards the center start to hurt progress because of pushback? I'd posit that much of the "Black Lives Matter" debate is actually this debate - But that the communities are speaking past one another. The places where Black Lives Matter is considered axiomatic are already past that line, while the places where it's viewed with disdain are where racism is still firmly rooted.
If some organization isn't meritocrous in how it promotes people and participation, the solution is to make it so. And it will take time for the effects of the previous bias to unwind.