I agree with you that there could, and should, be a minimum “baseline,” if you will, of living standards. And I believe that is possible.
However, when you start talking about global social equality, or communism–where everything is shared equally, true global equality, you’re opening a whole new can of worms. While a resource-based global economy may be possible, similar models have been proven to fail (but that’s a whole other debate).
The way I see it, every individual is different and has different functions. Communities are all different, and have different functions. To say no one can use, buy, or create something because it is not sustainable for all is like throwing the baby out with the bathwater. There are many good things that are perhaps unsustainable that nevertheless provide inordinate value to society. Again, the overall balance is greater than the individual.
You mention that inequality doesn’t provide motivation for change and that instead, the desire for improvement causes change. But what is the root of that desire? The desire stems from those who see problems and want to fix them. If everyone is truly equal, what will the problem be to fix?
And that’s where this all comes from. Because I think people naively believe if everyone is equal, and everything is sustainable then there will be no problems. Theoretically, perhaps. But not when you take into account human nature and greed. There will always be those looking for an edge, for more power. Even if somehow the elite of the world today crumbled and your vision was actualized, someone would take their place.
Or maybe I’m full of shit. Either way, I support the principles behind the post, but perhaps not the methods.