It's not so much that a different setpoint is worse per se "at steady state", it's that the world has been in a fairly steady state for quite a while now, with

It's not so much that a different setpoint is worse per se "at steady state", it's that the world has been in a fairly steady state for quite a while now, with little variation, and our structures have grown to depend on that particular state. Think of the locations of cities, the allocation of agricultural crops in given regions, the whole economic system built up around that, etc. Essentially we've been able to rely on things being a particular way for ~10,000 years or so, and if things keep going the way they are everything will (a) be different from what we've grown to expect and (b) be changing unpredictably for a while to come, meaning we can't just set ourselves up for a new configuration. This is the way I understand it, anyway.