Organized religion is almost always a monopoly. Legalization of mind opening substances would lead to a free market of ideas that dogmatic superstructures cannot survive.
In a culture that prides itself on a bizarro academic sense of rationality, there is zero rationality in the popular way we view spirituality period. None whatsoever. So like, even though nothing else in our society works this way, the best way to understand spirituality is by obsessively reading the same book over and over again. But aren’t there like, other books? Well, sure, millions of people have written about various spiritual practices and disciplines throughout history but all that stuff’s just crazy woo woo nonsense. Just keep focusing on that one book. Everything you need to know is in there. Each religion has their own special book and it’s rather sad that I can sum up the underlying philosophies that have come to define their more conservative strains in 2 words: more babies.