Ancient world? The Roman Empire fell apart. You know that, right? So, turns out their worries were warranted. A culture, a civilization can go through a period of stagnation and decay, and it eventually dies. Then there's a lengthy period of chaos and eventually something else may arise. But we're talking countless generations lost in that noise.
Currently, our civilization is more united than ever. Monoculture. Not only the Western World, but The World. We're united through communication, technology, everything. And when we all start declining at the same time, through many objective metrics, mind you, including the decline of democracy worldwide, the terrifyingly low level of public discourse, reduction and profanation of our vocabulary, inequality, collapsing demographics, climate, wars etc. it's grim. It's grim, because there is no clear alternative arising... except AI.
And I don't think we want AI to be an "alternative" to human civilization, that wasn't the plan, was it?
See, that's the thing, we look around, we see the technology we live with, and we feel very personal about technological progress, as if you and I personally invented everything from the wheel, through electricity, to computers, networks, and AI. We feel in control, we feel smart, we feel so Personally Intelligent (tm) for having technology. We feel "wow, clearly if we have these sci-fi things, we're on the up and up". But technology is not you. It's not me. It has taken on a life of its own. It serves capital, not the people. As technology gets betters, humans get worse. So tech progress is not the story you think it is. And it doesn't end how you think it does.
With apologies if you're being ironic.