The Tulpa stuff has been reinterpreted in materialist terms too (apparently 80% of people treat it this way, from some study or other).

Of course, interpreting these things in just one way is a category mistake.

The mystical stuff cycles around about every 25 years, but comes in from a different direction each time. The last boom was around the millennium.

As for the traditional religion, my guess is it's traditionalism in response to the increase in cultural warfare we've seen recently.

I interact very often with young people both online and in reality (barring the article's mention of several such things), and I see the same trends you mention. Some of it has always been mostly the purview of youth, such as interest in exploring known religions and inventing "new" ideas about the whys and hows of existence. Specific topics such as renewed interest in tulpamancy, dream interpretation, and chaos magic[k] I think can be traced roughly to a reflection of modern society: a desire to make sense of and control a world in which you have increasingly less control. As populations and communications grow, the signal to noise ratio that any given person experiences increases, leading to less sense of "I know what is what".