What you presented there (and here) is another theorem, something that should be proved (and published, if it hasn't been yet). If true, this gives an estimate on how dangerous a non-agent AGI can be. And yes, since we have had a lot of time study people and no time at all to study AGI, I am guessing that an AGI is potentially much more dangerous, because so little is known. Or at least that seems to be the whole point of the goal of developing provably friendly AI.