I don't think I've ever heard someone who opposes DEI say "we should fix our broken economy instead". But it's not wrong - the problems of racism and classism are uniquely intertwined and need to be fixed together.

The way DEI is usually framed by opponents is less "companies are using DEI to buy woke points so they don't fix the real economic issues" and more "companies deliberately hired unqualified black lesbians to tick a checkbox". These are very different critiques in terms of who they're aimed at. The latter makes it sound like we just need "more meritocracy" - i.e. to fix the problem by firing all black and poor people. The former makes it clear the problem is the people running the economy who are pitting different groups of people against one another to keep labor down.