You don't need psychoactive drugs to have deep, earth-shattering mystical experiences, and I don't understand why one would want to rely on drugs to get them.
Maybe not.. but psychedelics seem to be the most reliable, easiest, and quickest way there.
Edit: to respond to your 'easiest' edit in -- it's only easy in the sense that the barrier for entry is lower, but 'lower barrier for entry' is optimising for quantity, not quality.
As for "quality", who's to say? Many meditators have never been heavy psychedelic users, so if they claim that meditation can get them to the same place they don't know what they're talking about.
That's not to mention that psychedelic experiences vary widely from person to person, and often even from trip to trip taken by the same person, so it's really hard to make generalizations that apply to all people, all substances, and all circumstances.
Also, some people dismiss psychedelic experiences as illusory, which to me just signals that they have nothing interesting to contribute to the conversation. I'm interested in exploring these substances and spaces, not in trying to sweep them under the rug or wishing they would go away.
Good luck trying to extract any words to describe it. Not that it can’t be done, but when you have a glimpse of more profound realities, who would expect it to be easy to articulate or execute upon?
But, in combination with weeks and months of effortful meditation and writing, outcomes can be had: https://doi.org/10.1016/j.sheji.2022.01.001