I think we're saying the same thing except seems like you're conflating DEI with tokenism which incidentally I have no issues with them dismantling because that was just malicious compliance.
DEI on it's own was always supposed to just be an accountability tool that exposed their "ratios". My educated guess is that gov thought a little "sunshine" in 'errbody's business would improve equality but it was a shame-based approach and shame-based anything never lasts.
Anywhoo it's moot now cause it's gone so now I guess time will tell to what extent it helped or didn't 🤷