Simon and his ilk owe their success to this: they have been right so far.
I would agree with that. I would also agree with the warning 'past does not predict future' but what I would prefer to see in such observation is the question of why Simon has been right "so far".
Its interesting to consider this is the light of downward movements in the predictions of human populations. It seems possible, even probable, that human populations are self levelling in a non cataclysmic manner.
There is no suggestion (at least I didnt perceive it in Simons work) that material will appear from nothing and that there is no need to be concerned, but there is a confident optimism based upon the research on human activity, rather that a refutation of the above principles