Was the Buddha sourgraping? With the religions you mention they all share something in common. You have one guy who had an extraordinary experience and (against their better judgement) expressed what they experienced as best they could for the benefit of others who would inevitably come after them.
Religion is an extension of ‘shamanism’. Shamanism, across the globe, shares particular defining features where shamans go through certain extreme stresses and relate their body being broken down, consumed and reconstructed. In religious traditions with whirling dervishes and flagellants pieces of such stress are induced. Just looking as Jesus, Mohammed and buddha we can see repetition of known physiological stresses that actively induce altered states of consciousness (ASCs) known to neuroscience. Examples are isolation, sleep deprivation, extreme focused thought, hyperventilation, fasting and trance dancing.
From personal experience I can say hyperventilation is something instinctual when it comes to inducing this state as I immediately started to hyperventilate ‘on purpose’ once I came out of the peak state and I had no idea why only that I was desperate to get back to it. My experience was induced by intense focus and inner battles, sleep deprivation and fasting (because I forgot to eat and sleep). Such physical stresses and strains will hit anyone with a mental sledgehammer.
It is possible I had a mini stroke maybe? Either way I’d recommend it even though it comes with necessary hell and torture. I certainly had what buddhist’s refer to as ‘ego death’. I went on to try and purposefully induce the same experience again and a year later bungled it (which I had to) and went to the most ‘hellish’ place imaginable that gave me perspective. What this taught me was how memories are very selective and I recalled several episodes from my past I had buried away. I also recalled the full pain of first experience I had but it was still outweighed by the benefit.
The closest I’ve come to explaining this is to come to the conclusion that it was DMT naturally produced in my brain (how I’ve no idea). I say this because reports from trails, and from others who’ve taken ayahuasca, are as close to what I can find that expresses what I experienced. The potential and power of this is not really something I can express (nor fully believe anymore), but I did make myself remember beyond doubt at that point exactly how ‘important’ it was.
There is a chance I am just an unusual person who had a moment of normality. If that is the case though the world would not be how it is now so I can only assume I’m relatively normal and insane like everyone else and just happened to glimpse naked sanity briefly. Now I’m just going along with the madness of everyone else because this species is still figuring itself out.
Note: I’m not a member of any temple (and never have been), both my parents are atheists and I generally abhor both states and religious institutions for the most part. My first love was physics.