Gregory Shushan, author of Near-Death Experience in Indigenous Religions (2018) notes in a recent article at Psyche that near-death experiences are not a new discovery:

NDEs have been popularly recognised in the West since the mid-1970s, but people from the largest empires to the smallest hunter-gatherer societies have been having them throughout history. Accounts are found in ancient sacred texts, historical documents, the journals of explorers and missionaries, and the ethnographic reports of anthropologists. Among the hundreds I’ve collected are those of a 7th-century BCE Chinese provincial ruler, a 4th-century BCE Greek soldier, a 12th-century Belgian saint, a 15th-century Mexica princess, an 18th-century British admiral, a 19th-century Ghanaian victim of human sacrifice, and a Soviet man who’d apparently killed himself but was revived during resuscitation experiments. NDEs can happen to followers of any religion, and to those of none.

Gregory Shushan, “Near-death experiences have long inspired afterlife beliefs” at Psyche

They are also not only the experience of religious people, as Shushan notes: “Upon revival from his NDE, the British logical positivist philosopher A J Ayer allegedly told his doctor: ‘I saw a Divine Being. I’m afraid I’m going to have to revise all my various books and opinions.’”

What’s really changed is something more mundane: Modern medicine can manage clinical states of death. In the past, it might have been hard to know if someone was really dead or just having a vivid dream, perhaps during a serious illness. Today, there can be considerable evidence that a person was clinically dead when he later reports, for example, that he saw the surgeon flapping his elbows to point to things. In that situation, the surgeon, trained in Eastern Asia, communicated by pointing his elbows in order to avoid contaminating his hands in the surgical suite. But there was no way that the patient could have known that apart from his apparent near-death experience.

Note: It’s not reported that A. J. Ayer revised all his books and opinions but — this is typical with NDE experiencers — he is reported to have become a much nicer person to deal with. He wrote about his experience here.

You may also wish to read:

Claim: “Evolution” explains near-death experiences The problem is, there is no evolutionary reason to believe the claim. Humans who have near-death experiences are not “playing possum”; they really are clinically dead but can be resuscitated by modern medicine.

Physician explains why he takes near-death experiences seriously Near-death experiences don’t fit easily into traditional science categories because they occur — often with life-changing effects — when the brain is damaged or unconscious

and

Why reasonable people think that near-death experiences are real Distinguished engineers Walter Bradley and Robert J. Marks sift through the evidence.