"There were a lot of unscrupulous gurus washing up on the shores of America in the 70's, but most of them had something useful to say about meditation"
I think you've still got a long way to go to put this guru wave into perspective if you think these charlatans had something useful to say about meditation. For that matter using Wilber as a reputable source is walking on shaky ground.
But you have asked that really important question for which I'd love an answer in the wrong place. You have to ask it of dedicated, intelligent, self-aware, truth-telling followers of Prem Rawat.
Here's a list of gurus who have felt impelled to impart the Eastern wisdom in the West. Which ones do you think were shining examples of the effects of meditation?
https://www.prem-rawat-bio.org/gurus.html
