An extinction event is currently ongoing that humans caused

We aren't gonna let another asteroid beat us to it. Not again, anyways.

That's because it's coupled with modern medical marvels, like the discovery of antibiotics, which has led to a wildfire of population growth. Also, the "Industrial Revolution" where we yoke machines into assembly thus yielding more output, which encouraged more population growth -- especially within the food sector.

Capitalism did exist in the 19th Century, but because Gangrene, Rickets, and other maladies, it was slowed. It was also slowed because electricity hadn't been harnessed yet.

Basically, this assertion is ignoring the crossroad of human progress: discoveries in medicine, harnessing electricity, Industrial Revolution and assembly lines, and recent electrolytic tabulation (aka computers).