I'm A Banana
Potassium-Rich
You may not be surprised that I agree strongly with what you say here.
I will add: my personal preferences in RPGing mean that I think a setting which tends to weigh against change is a problem; because it creates an obstacle to player protagonism via their PCs.
This is also why, though I like many of the tropes of Dark Sun and admire the way that the 4e mechanics are put into service to make the setting work, I am not sure that I actually want to use it for roleplaying.
Having actually played PS and 4e Dark Sun, I can say that there is little in either setting that could be conceived as something that will "weigh against change."
Planescape is a setting where reality re-shapes itself according to the power of the ideas the player characters wield, where the PC's define the cosmos.
Dark Sun in 4e at least is a setting in precarious, fragile tension, where the powerful NPC's are stretched thin and reaching the breaking point, just as the world itself is. And I didn't play it in 2e, but a world of dying nature would seem to be ripe for heroes to enter and set things right by restoring the natural order.
Change seems to me to be part and parcel of what the PC's are meant to bring in either setting.