Yes, but does that make it any less true? Essentially what this study is saying is that, when we DO have an incredibly meaningful experience, the same thing is happening in our brain as happens if we are on these psychedelic drugs. Is it a less valuable experience if caused by drugs than if caused by, say, prayer, meditation, or powerful emotion? Why? It's the same experience, it means the same thing. Is it better to go through your whole life never experiencing a powerful sensation of unity with everything, or to have to use a drug to reach that state? But yes, I personally do think it's more valuable to reach such a transcendent, mystical state through years of study and meditation than to do it instantly...however I still think everyone ought to strive for such knowledge, one way or the other.
Terrance McKenner said sort of the same thing. He was talking about the drug DMT (a hallucinogen like psilocybin that is traditionally found in ayahuasca). His idea was that the chemical DMT was released in our brains at significant moments in life - mainly birth and death.
He had an interesting theory about psilocybin mushrooms and human evolution.
People all over the world have been using ethnogens in order to evolve spiritually. I don't think it is a lesser experience because of the presence of mind altering substances. Maybe we need to have our minds altered?
There is a guy at my uni doing his honours thesis on DMT (within studies in religion). The experiences that I have heard about don't seem to be similar to OOBEs or NDEs. They are usually highly visual with no physical affects other than mild euphoria and/or relaxation (unless you are taking a compound which contains 5-OH-DMT, which can be quite an uncomfortable experience). BUt suppose this sort of thing will always differ from person to person.