The power here is supposedly that no authority can override your desires on your plunder system because it will eventually be a frozen spec, and so virtual machine runtime implementations that are correct must run any program from any time after the freeze. That means a vm I make today will run programs a thousand years from now (probably inefficiently) and a vm created in a thousand years must run programs from today. Theoretically speaking.
Yes that's what a spec means. Like wow I can write puts("Hello, world!") and it does the same thing on every ANSI C compiler, how novel!