When you get down to it, the real cost for everything is energy. If our society survives long enough without nuking ourselves out of existence, we'll have AI and robots capable of doing anything a human could. Robots don't care about money. The only thing you can pay a robot with is energy. Think about it, the only thing really worth anything in the universe is energy. What's that? You need some really rare material that can only be found on an asteroid hurtling through space. Well that's gonna take a lot of energy. Energy to power the supercomputer that will design an ideal ship. Energy to power that ship as it flies through space. Energy to harvest that raw material and bring it back to earth. Energy to refine the material into something useful. Think about why anything is valuable. A laptop for example is somewhat expensive. What does that expense cover? The various metals that are mined out of the earth with excavation tools that take up lots of energy. The engineers and programmers that spent lots of energy designing that laptop. The machines that use lots of energy to put the various pieces of your laptop together. Do you get what I'm saying? EVERYTHING costs energy. The sooner we realize that energy means everything, the sooner we can advance as a species.