That's a meaningless claim, devoid of any evidence. At most points in human history there were decent reasons to think we were near the peak. And yet with some occasional temporary valleys, average human living conditions continued to improve.
At most points in human history, the global economy was not so tightly integrated, and major powers didn't have the ability to devastate the globe in an afternoon.
There is a significant meaning to my claim, which is that it's unconvincing to make exactly the sort of "it has always worked out before" argument that you're making here.
