In the 80s there were many cases where a minority candidate wasn’t hired/promoted and the job went to a less qualified candidate. That’s VERY rare these days - employers now want the best candidate who will take the salary they budget for the position.
In the 80s employers went overboard with quotas and it still happens today even if they call it diversity instead of quota. By definition, diversity programs do not hire the most qualified candidate. That means
A) The company/organization will probably not do as well as they can
B) Less qualified diversity hires won’t do as good as their peers and make diversity programs look bad even when the diversity hire receives extra mentoring or lighter load (which looks bad to everyone else)
C) Moral goes down when better qualified employees are passed over for a “diversity promotion” (and the diversity-promoted manager will have a more difficult time than a qualification-promoted manager because of their own qualifications and the extra moral problem. Repeat A & B)
That’s a recipe for failure for the business, the diversity program, and individuals in position because of the diversity program.
That doesn’t even count the woman who never wanted to do STEM in the first place but saw a college and career path that looked appealing 10 years ago because of the scholarship and hiring practices for women. But some are not happy with STEM 5 years into the career. Some women are awesome at STEM careers and love it. The others are working with peers who love it while they want to find another career but are locked in for many reasons until they get to management - tough to compete with peers in that case and get to management. (Or pick any other minority and diversity-based education and career sales pitch)
Something else I've noticed is that "workplace diversity" has resulted in many situations where an employer basically has a two-tier system of employees: the ones who get their on merit and connections, and the "diversity pool" of all the others. What ends up happening is that the diversity pool groups simply end up competing with each other for positions in that pool.
Consider an employer, for example, that institutes an unwritten rule where 30% of the employees will come from the groups that make up the "diversity pool." This just means that the various racial/ethnic/gender groups that make up that 30% succeed at the expense of others -- but only at the expense of other racial/ethnic/gender groups in the diversity pool.
This is why I predict that inter-group strife between various protected classes is going to end up bringing the whole charade to an end.