so effectively you are saying that everything for 36 years has pointed to a logic for increasing minority and women's participation in the workforce
1. Higher participation rate in college
2. Studies that "prove" diverse teams are more productive
3. Social justice policies that put huge pressure on employers to hire minorities and women
and yet they still aren't there???
So as a business owner I have more women and minorities to choose from, AND I'll be more productive, AND I'll stay off of the racist/sexist/bigot/homophobe/etc naughty list and yet I still choose to not hire these people,...hmmm...not to mention that at least anecdotally it appears to me that HR staffs across the country are dominated by women and minorities these days (one would presume that they are giving their own sub-group at least a fair shake in the resume queue) ...and yet we are still having to have marches, etc..
That just doesn't jive. My suspicion is that these studies you mention were so contrived and manipulated to deliver a desired outcome that they don't resemble "real world" teams in the slightest. If companies were truly experiencing higher productivity by being diverse, they would be clawing and scratching to find these force multipliers. I'm not saying that there aren't women and minorities that can stand toe to toe and hold their own in the workplace. There are many, and there are many that are more productive and more capable but the instances (outside of branding/marketing) where a specific sub-group perspective added to the productivity of the group are so few and far between as to be almost non-existent.
Diversity does not lead to higher productivity. Better, smarter workers (no matter the gender/race/ethnicity) is what leads to higher productivity. If you are the better, smarter worker you should get the job...companies/schools shouldn't hire or even focus their recruiting based on specific sub-groups.