In my opinion, it all revolves around the lack of foresightedness.
People consider themselves eternal and hate death. They don't want to die and delude themselves that death doesn't exist.
That is why they believe everything is eternal: resources, spaces, etc..etc..
My generation is called the childless generation. We Millennials are the childless generation; just think that in the last high school reunion, only 5 out of 25 classmates had children, I found out. Five out of 25.
In a decade most female classmates will undergo menopause...so it's a definitive number.
Our generation has been inculcated since youth that the world was overpopulated, that the world was filled with so many problem.
The mere idea of creating babies that will have to live in this nightmarish world...terrifies us.
It terrifies me.
We are the most spiritual generation because we were raised to think that matter is ephemeral and that only spirit remains.
Millennials see sex not as a procreation, but as spiritual experience.
I'm technically a Boomer, though close to the cusp with Generation X, so I could probably identify with either one, at least in terms of shared cultural observations one might have while growing up at the same time.
I can see that, at the beginning of the industrial revolution (which was also a time the entire planet was being explored), it probably seemed like it was a land of plenty. There was all kinds of wealth out there to mine or grow in accommodating climates. The world population was still relatively low, so a lot of land lay open and seemingly unused.
But by the time we reached the middle part of the 20th century, more people were starting to see where all of it was heading. Even if there may have been a lack of foresight at the beginning, there was a point where we started to see the handwriting on the wall.
It wasn't merely a matter of overpopulation, resources, or environmental concerns, but also concerns about the technology trap itself. We reached a point where we became so industrialized and so specialized that we have grown inextricably dependent upon the structures and systems of a modern industrial society. All of these systems depend upon each other and must be constantly maintained and supplied, or it could conceivably fall apart very quickly.
I think most people realize that we're kind of living on a house of cards here, but there's also the realization that we can't realistically go back. We might try to cut back on consumption, use alternative forms of energy and transportation. If technology and industry put us into this trap, then maybe a way can be found to get out of it.