Are resources limited, scarce? Or nearly unlimited? Is the planet fragile or robust?
Simons presented clear, convincing arguments as to why resources were nearly unlimited. Erlich argued that resources were limited, and that this would result in massive near term starvation. We know who was right, of course.
It's also true that many of Erlich's arguments are being repackaged in the form of Global Warming Hysteria.
Right you are.

Just as Malthus failed to anticipate tractors, Ehrlich failed to anticipate the substitution effect.
Simon's key insight is how human intelligence-driven innovation ("The Ultimate Resource") provides unlimited fuel for the substitution effect.
Today, the ManBearPig hysterics are similarly misguided by simplistic linear thinking, as they fail to account for phenomena such as emergent properties, hidden variables, and disruptive metasystem transitions.