Did we know of X rays till Roentgen came along? Did we know of microbes till whoever came along? Did we know of Dark Mater or Dark Energy till recent decades?
Yes we knew about X-rays before Roentgen, he proved the theories about them and came up with reliable ways to generate them, but he started from what we could detect.
The germ theory of disease was around before Pasteur proved it.
We don't know of dark matter or dark energy; those are terms for notional causes for effects that we can detect but can't yet explain.
Afterlife is not even that, we have no observable effect which requires an explanation.
Science has to catch up with reality.... ideas have to mature...technology has to be available.
To investigate what? The NDE's that you talk about have been thoroughly investigated, and the best supported explanations do not come down to 'spirits surviving beyond death.' Science IS investigating the claims of afterlife, and it's finding those claims to be wanting.
Sometimes technology is not enough. Can technology help us see strings or 11 dimensions? They will remain on paper.
Technology moves forward, though; the point of string theory, and the reason it's a theory (and, say, dark matter isn't) is that it's hypothetically testable, we just don't currently have the capacity. Just like the Higg's Boson was when Higg's postulated it, and now we do have the technology to prove it.
Reality could be much more complex than we imagine.
Reality already is more complex than we typically imagine; that doesn't mean that every notion that any crackpot comes up with is as valid as, say, germ theory, or Higgs' Boson or, even, dark matter.
O.