You are assuming people have fixed minds, and wants never expand to fill the available resources.

I never assumed people have fixed minds. People have complex and ambitious minds. But largely these ambitions are social, and not material. Even "materialistic" desires are rarely about the actual material, they are almost always about the social significance of the material.

Regardless of how perfect the ‘setup’ the remaining materialistic desires will continue to expand as population and technological capacity grows. There is no known force that can completely extirpate such desires. Since there is no upper limit, all available mass-energy will inevitably be utilized given enough time. You are arguing that such a progression can be delayed, I agree. Perhaps a delay is possible up to millions of years but that’s just shifting the timeframe.

For example, I’m fairly certain I’ve encountered someone that genuinely wants an actual Star Trek like spaceship for their personal use, with a minimal social signalling component.

Even if there’s only 10000 such folks on Earth, that already represents vastly more industrial output than real policy makers can even dream of realizing. Let along the current and future desires of everyone else.