When in reality, modern industrial agriculture is one of the most ham fisted and naive approached to the problem: just bulldoze, fertilize, irrigate, and spray everything into submission. With many negative consequences of course, which we generally refer to as "unsustainable".
Because understanding all the complex relationships within an ecosystem, and then how to engineer it to yield surplus material for human use without intolerable negative consequences, is in fact a cutting edge and poorly grasped science.
The "biocultural legacy" is an empirical approach to this problem refined over milenia, which we would do well to understand and appreciate.
The "green revolution" (a misnomer with our current use of the word) sure was effective; the point is that it was also unsustainable.
Of course the land has a finite carrying capacity. And I'm not anti-ag-tech either. In fact I believe higher precision and intelligence is the answer. We need to create highly diverse and cohesive ecosystems tailored to the local environment, which requires lots of observation and iteration.
The exit for Malthusian traps is to temporarily have enough abundance to reduce the birth rate dramatically not simply to steadily increase food production. Being unsustainable isn’t actually a problem if the total population starts dropping.