An interesting note to what is science fiction, can be found in the you tube interview. P K Dick says that in his early years, some editors thought you needed a rocket ship in the story for it to be science fiction. He described an even funnier description of what could be called science fiction by the big publishers. The rule was simple, if a science fiction story had a couple of swear words which could be taken out without changing the story, it was science fiction. If a science fiction story had a lot of profanity in it, which could not be taken out of the story without changing the story, then it was mainstream literature.
Fiction is the greatest escape vehicle ever designed. Reading is the easiest route as it takes a lot of time, even if you have to read several books, it still takes you away from reality. Even without a written book, no matter how bad things are, you can dream up a story, either your own, or a rehash of something read, or a mixture of whatever you want to remember.
At some point in time, P K Dick started thinking that the universe we see is god first, and secondly, it is seen/experienced as whatever illusions we make out of what we see. We are wandering around in the god that is the universe looking for god.
Unlike the supposedly real world, fiction has no rules, no constraints. This allows people to compare anything they want to anything else they want to compare it to. Originally, the word religion was always about a way of life that somehow gods or a god would be involved.
In the 1960s and 1950s consumerism became a religion because it now gave people a way to celebrate or practice beliefs in a common way, with everyone using the same implements.
P K Dick had a negative transcendental experience in 1963 that caused
him and his family to attend church services for a while. He wrote The Three Stigmata of Palmer Eldritch in 1964.
This could be more connected to his 1963 experience than what other writers, including Herbert, were saying at the time.
Stories about religion now have a lot of latitude of what can be included in the story. Dune seems to be an honest attempt at creating a religion in a science fiction/fantasy world. While it includes drugs, the drugs bring people into the real world.
The Three Stigmata of Palmer Eldritch explores some very basic tenets about religion, but to me, it also looks more like a mockery of modern religion. The story features as one article states, the Stigmata are alienation, despair, and blurred reality. It is presented in a comedic manner where one world based on drugs is replaced by another world based on drugs. The drugs allow people living in dreary circumstances to share pleasurable existences within each other's minds.
The shared experience becomes using drugs so everyone can exist in another person's hallucination where one can find god by believing what one wants to believe. Thoughts are repeatedly modified step by step to create the desired look of the world and the people in it, inside someone else's hallucination. The hallmark of the hallucinated world are the Stigmata, which have been transformed from the wounds of Christ into artificial body parts on the inhabitants of the hallucinated world.