Its hackery all the way down though.

Not only does his theory not account for changes in growth rates because things will naturally adapt to fit their environments (I would personally argue the reason you have seen so much slow down in national growth rates is a natural realignment due to many nations being overcrowded).

Not only does it not account for increased productivity that can fix the issue that is being shown (See: Green Revolution, and the rumors here in farm country is we are about to have another revolution in farming).

You want to know the event that Malthus used as the basis for his theory that there is an upper limit to population and you need to do all of the extreme control on it? The Irish Potato Famine. You know, one of the most infamous man-made famines in history! Ireland made enough cereal crops to weather what was happening. It would have sucked, but they could have made it through without the potatoes. Except that then the English came in and said "Ours now" and took all of their own crops to distribute it back to them in amounts not nearly high enough. And this is the entire basis for his theory.

He is about on par with Lysenko as far as "smart scientist" go.