Yes, but different people will care more or less about different things and thus vote for different parties which all have to work together to form coalitions,

Yes, but different people will care more or less about different things and thus vote for different parties which all have to work together to form coalitions, which in theory then have to reflect a negotiated compromise among the different things that different people care about. It’s not perfectly efficient, and it can suffer from the problem you’re describing, but far less severely than the US system does.