Tom Stafford on why policy preferences don't neatly create "median" or even "centrist" voters in practice:

In one-dimensional space, like that of the traditional left-right divide, the centre is densely populated and closer to each of the extremes than the extremes are to each other. In a high-dimensional space our intuitions break down. Nobody is truly in the centre and every individual is ‘next to’ every other individual on some dimension. The logic of high-dimensional attitude spaces is horseshoe theory on steroids.

This doesn’t mean centrism is impossible, only that you need to think of it differently. Conceived of as a space, the centre is empty, the median voter doesn’t exist and wouldn’t be representative anyway. But seen as a network, you can imagine the people in a polity, holding their diverse - often maddening, sometimes contradictory - beliefs over multiple issues, with everyone connected to everyone else by some shared views (and everyone distant to even their closest allies, by a difference on some non-shared view). Within this network, many possible coalitions can be found.