I experienced this first hand and as a result I departed for greener pastures. Isn't diversity a great thing when it suppresses wages, no wonder all the big boys are pushing for it.
Of course, everyone who gets a competitive offer elsewhere will get a counteroffer, so this policy only applies where it’s convenient.
I'm all for paying people in lower-end jobs better, mind you, but using this as an excuse to hurt salary growth seems like it's intended to discredit the whole idea of gender equality. Well, unless the people involved are provably overpaid, like CEOs tend to be. But somehow I suspect the CEO is still getting his excessive raises.
Very simply, the measure of women being paid less is useful on wide scale in demonstrating women's position in society, but it doesn't go into the complexities of the issue, so aiming to get your company more equal on that measure can mean so many things as to make it a useless target unless you understand the situation.
But that test doesn't mean that movies that pass the test are better or more feminist than movies that don't. Terribly sexist/misogynist movies can still easy pass it, whereas Gravity, a movie starring only Sandra Bullock for most of its duration, doesn't pass it because there's nobody else in the movie to talk to.
Similarly, the point of calling attention to the gender wage gap should be to pay women better and give them better access to higher paying jobs, not to deny men raises.
Equality should lift people up, not push them down.
Your model makes no sense. If powerful forces wanted diversity out of self interest all along, we wouldn't even have a diversity movement, because the environment would be diverse already due to natural locally optimizing market forces, so there'd be nothing to advocate for.