These politics only appeal to ~10% of the population anyway, and they aren't favored by a majority of any ethnicity. This stuff isn't mainstream because voters like it (which is why it never makes its way into any real laws), it's mainstream because the cultural and media elites like it and they don't have to trifle with a democratic process to impose it.

Corporate DEI stuff is also useful to "prove" that an employer isn't racist--current anti-discrimination law puts the burden of proof on employers to show that they didn't discriminate, and since it's not possible to prove a negative, they must instead compete to show that they're among the more 'woke' companies ("look at our DEI propaganda, how could we possibly be guilty of discrimination?").