Malthus was refuted by the early 19th century on economic grounds - namely that the pricing system prevents people from over-exploiting scarce resources.
While there has certainly been some poor husbandry of the earth's resources, there have been and continue to be significant efforts to improve resource utilization in environmentally friendly ways - not the least of which is increased costs of basic resources leading to self-imposed limitations by consumers.
Basically, on net, people choose more luxury over more children. They economize when presented with prices that reflect the reality of underlying scarcity. They make choices that often result in improved environmental stewardship, either implicitly or explicitly.
Picking something unlikely but possible, imagine if water becomes scarce enough that half the population of India can't afford market price and must do without.
That thought is pretty much enough to refute the refutation. The idea that a resource can't run out because "economics happens" is simply a non-sequitur. Economics is perfectly comfortable with optimising a bunch of humans out of the system because they can't produce enough to justify their resource consumption. That is what a Malthusian collapse would look like economically speaking.
A Malthusian collapse would entail running out of resources because the population grew too fast, not because the resources are otherwise affected. Conditional on some constant access to a shared resource, the price increase would smoothly counter the population increase, bringing everything back into stability without ever leading to massive starvation. Supply shocks are certainly a thing, but we have not seen anything like a Malthusian collapse since he wrote about it.
> if water becomes scarce enough that half the population of India can't afford market price and must do without
This would require importing water and/or energy. If there was an ability to pay by the government, desalination would create new fresh water. There probably wouldn’t be, which would cause short-term pain, but that’s the feedback mechanism OP alluded to.
While there has certainly been some poor husbandry of the earth's resources, there have been and continue to be significant efforts to improve resource utilization in environmentally friendly ways - not the least of which is increased costs of basic resources leading to self-imposed limitations by consumers.
Basically, on net, people choose more luxury over more children. They economize when presented with prices that reflect the reality of underlying scarcity. They make choices that often result in improved environmental stewardship, either implicitly or explicitly.