Well. Human societies have an upper limit on the amount of population they can sustain, determined by their access to natural resources, technology, and social organization.

Malthus got a lot of shit because he came up with his theories exactly when civilization was entering into a period where the advancements in technology were drastically expanding those limits, and because his ideas were instrumentalized by a lot of unsavory types, but he did find a (very incomplete) segment of truth.

Right now, the biggest danger of it all becoming relevant again is the possibility that sustained ecological disaster might dramatically lower our population upper limit without us having the capacity to react fast enough.