That is a decent rational, except that whichever rich nation makes the breakthrough (assuming it occurs) will not have a monopoly on the technology (unless it i

That is a decent rational, except that whichever rich nation makes the breakthrough (assuming it occurs) will not have a monopoly on the technology (unless it involves mining He-3 from the moon), in which case the rich nation that invested in lunar mining technology will have quite a jump. It's pretty hard to keep big engineering secrets. As soon as the feasibility is proven, the fast followers will jump on the bandwagon.