It is ridiculous how wasteful we as a species are. It is upsetting. I was listening to a story about the former U.S. President Jimmy Carter and his wife. They were people of the great depression and lived like it even after his years as President. The story recalled how they would wash out ziplock bags, dry them out, and reuse them. How many people actually do that these days? I know we don't. It's sad really.
There's so many things each and everyone of us could do better, but we generally don't.
You mention the Carter's and it made me think of my dad who grew up in Japanese occupied Malaysia (then, Malaya) during the second world war and the terrible existence he endured through the Japanese soldier's brutality and the lack of pretty much everything. As I got older I came to understand more and more why he was so frugal, so careful to look after what he had and the way he worked on using as little as he could when it came to resources. I don't want to go into it here, but I came from a family that struggled financially and while it wasn't at all like the Great Depression the lessons were the same. I'm glad I had that upbringing and I've carried the lessons forward.
These days I can buy pretty much whatever I like, but I don't unless I need it and I think that is something so many don't know how to do. We should be conserving but most are consuming with voracious appetites and little regard to the future implications.
I think in the future, many are going to relearn some of those lessons whether they like it or not. Like you have said, this can't be sustained and eventually everyone is going to pay for it. Most likely not in our lifetimes, but it will happen.
I agree, there are tough times coming and I don't just mean in third world countries. Many will suffer and...maybe then there'll be some change? Maybe not though...certainly a reckoning though.