Centrism can work reasonably well when left and right have significant overlap, as was the case in US historically for most of its existence. That overlap then tends to have policies that both sides think are good, which, while far from a perfect filter, still manages to remove a lot of really bad ideas.

But when parties are so far apart that there's a gaping gulf between them, centrism becomes less about specific policies and more about "can we all get along?".