Properties like the binding energies of molecules and nuclei are a direct and well-understood consequence of the laws of physics. Materials in the real world aren't like Star Trek, where dilithium and the omega molecule can be treated as an infinite energy source because the name sounds cool. In order for a material to be an energy source, that energy has to come from somewhere.
You can only put so much strain on a chemical bond before the electrons decide to stop sticking together anymore. You can only get as much energy out as the mass change from splitting an atom. You can only store as much energy in a heavy nucleus as was originally put into it by the supernova that created it. Anything else would violate basic laws of physics, to such a degree that everything in our universe would presumably immediately cease to exist.
> No, we do not. Google "island of stability".
I already addressed the hypothetical island of stability in the sentence immediately after the one you quoted. The term is relative. They are expected to have longer halflives than the instantly decaying superheavies like ununoctium, but even the longer predictions of their decay properties have them disappearing far too quickly to be mined as minerals.
I'll add now that there's also no reason to believe that island of stability substances, if they even exist, will have any more particularly useful or powerful properties than any other heavy metal. When was the last time you needed to use Mendelevium for something?
> Yes, but that has nothing to do with the argument we're having. It doesn't disprove that there might have been some rare resource (or maybe it's still here, we just didn't get to it).
It disproves the idea that there might be some useful resource which you would want to go conquering for. The resources available in any star system are already more than any conceivable civilization could ever use.
The other side of this is the difficulty of interstellar travel. Reaching relativistic speeds implies turning a significant fraction of your vehicle's mass into energy. With the ability to create and manipulate such power densities, you're better off just synthesizing whatever you need.
> No, it doesn't. You don't know what you don't know.
> But maybe there was, that's the argument.
> Again, you're talking about known science. Not everything. You don't know what you don't know.
If the argument for suggesting a complete break from the known laws of physics can be summarized as "You don't know what you don't know", then you may as well argue that the universe is secretly controlled by a giant space cat which will reward us with salmon if we all shine laser pointers in our retinas every third Thursday.
"Maybe there was" is not actually an argument, in the sense that there is neither anything specifically substantiating it which can be examined, nor any falsifiable conditions which may disprove it.