I'm not a fan of Melon Usk, nor billionaires in general, so you can put your favorite straw-man away.

> Material science and energy output are the problems and are possibly solvable in the future.

This is the part I'm talking about. I've been reading the same pie-in-the-sky bullshit since the 90s, and it always comes down to needing that next breakthrough first. I'm highly skeptical that anyone is figuring out matter with negative mass or cold fusion in either of our lifetimes.