We can but we don't. Our biological drive, coupled with our lack of volition to reason about it, is to reproduce. Most people don't care if pumping out a unit is the worst thing contribution to the planet's environment, they'll do it just because.
This idea doesn't grok with falling birthrates in wealthy nations. People don't just live to reproduce. There is a biological drive to reproduce, but it is not unchecked. So the cancer metaphor is apt.
Island nations have always had to deal with the realities of Malthusian limits.