It's interesting that comparative research on the substantive outcomes of electoral reforms do show that not only are policies more progressive as a result, in the sense of pursuing collective advance, and being more in the public interest, because, in fact, you have to find common ground with other parties so that the public interest prevails, but they're also more enduring.
It's interesting, just as a sidelight, that despite concerns to the contrary, countries with more proportionality also have more sound fiscal situations.