In the west, the last decades have been marked by prosperity. After the big wars, there was abundant energy, relative geopolitical stability, so everything was improving for everybody (we can use more energy to build more machine to produce more stuff that becomes cheaper so we own more and we are happier).
Now we see that we have:
1. An energy problem (we're reaching the peak of fossil fuels, that shows in the economy, and we don't have a viable solution for saving the growth).
2. A climate problem, which means that even if we discovered an infinite source of fossil fuels that could save the growth, we would still be screwed because climate change will eventually destroy society as we know it (and probably kill many (most?) of us).
3. A biodiversity problem, which means that even if we discovered an infinite, clean energy and somehow saved the climate, the very consequence of our growth is habitat loss. We're living in a mass extinction that's orders of magnitudes faster than the one that killed the dinosaurs. It's a fact, it's measured. Say we could have a fusion reactor in our smartphones, we could still not eat it.
It used to be that everything was going well, and therefore technology was just allowing us to own more and be happier. Now we realise that all of this is not sustainable. And technology is what allowed us to get where we are, and it doesn't look at all like it can save us. The sustainable way is "doing less with less".