If they would even look around the city they could witness the resilience of nature. For example, one of the sidewalks where I walk my dog crosses a utility easement for about 200 feet. No one maitains this section and the sidewalk is cracked and coming to pieces from the weeds growing through it.
You are correct.
Think also of Pompeii, Chichen Itza, or Angkor Wat. The largest cities of their time, overtaken by vines and volcanic dust.
The environmentalists are nearly insane in their denials of reality.