Most DEI programs at big companies ended up setting goals based on things like race and sex. Zealots in HR departments then started implementing programs to change hiring and promotion and compensation to implement progressive identity politics at work, under the DEI label. These things happened in secret, because the companies didn’t like to highlight how being the wrong race or sex means your career is worse off.
That’s totally illegal and discriminatory but companies were not facing consequences for it under the Biden administration. The constant injection of DEI politics all over society - at work, in movies, in ads, etc - led to a backlash and personally I think it is one of the things that led to someone like Trump being re-elected. And this administration is very against DEI ideology. That’s one reason corporations quickly abandoned it - they didn’t want to face legal scrutiny now.
Another is that DEI culture produced no positive results, as expected. Companies already had incentives to hire the best employees they can. If you change that with other incentives thrown in, it’ll make things worse. And ten years after DEI began to appear everywhere, it was obvious it produced no benefit at best, and led to worse teams at worst.
Another reason is simply that a lot of the activists pushing this type of ideology grew out of the activist age group. And I think many of them likely don’t hold those beliefs as strongly anymore. But either way, younger people are different. Especially young males who are more conservative.
All of that and other things has led to DEI being removed or at least de emphasized.