I've tripped that intensly numerous times. Power of suggestion is almost everything. Psychedelic drugs are mirrors. The vast majority of what one sees in them is not an attribute of the mirror but an attribute of what is in front of it the mirror. One just doesn't have any ego control over the suggestibility at high doses. But it is still the mind, the deep recesses of the subconscious, that generates the suggestibility.
And in fact I see many people use psychedelics for years and not realize this. They attribute too much of the experience to the drug and not to themselves. They say for example that these drugs are entheogens, meaning "generating god within". Generating? Generating god? No, these drugs do not generate god (or any other realization) within you, god (or any other realization) is already within you. The drugs just wake you up to it, for a while.
So IOW, IMHO, whatever lasting "insights" you get from DOC are not properties of DOC. They are properties of your mind and wisdom. Thats why others will take it and not have such "insights".