Well, we agree that propping up the pyramid scheme is a problem.
Nonetheless, it is a good point to make when someone virtue signals about caring for the environment while they run around with a pack of unruly kids.
You know, I found Doug Stanhope unconvincing. Virtue signalling aside, if someone genuinely cares for the environment, and is making effective changes to their lifestyle to reduce their family's environmental footprint. I'll wish them well in having a dozen kids. Doug's offhand mention of a study will be based on the average polluting citizen, and an environmentalist is not that. Assuming these dozen kids retain the environmental concerns of their parents, they're exactly what the world needs.
Granted some "virtue signalling" is shallow and hypocritical - in which case there are many "good points" that could be made and likely ignored.
I'm not suggesting this be adopted as a general strategy (although there are undoubtedly far too many people around, most of them fairly worthless). You're right that this would cause a crisis and the government would be obligated to prop up the pyramid scheme. That says a lot. Any system whose stability is predicated on infinite, exponential growth is bittle and will eventually fail catestrophically.
Nonetheless, it is a good point to make when someone virtue signals about caring for the environment while they run around with a pack of unruly kids.