I don't disagree with you. I think there's an even argument along these lines that we don't really have free will, since our initial biology and environmental circumstances aren't within our control, and yet every subsequent decision and choice follows inexorably from those initial conditions.

To me, this inspires empathy and care, and it's why I believe that society should have a very high floor. But discussions like these, and the current "eat the rich" zeitgeist seem to focus so much more on lowering the ceiling. Which to me is the wrong focus.

Not really? If the same value and wealth is being created - the redistribution of it raises the floor as well.