I have no doubt it's possible to activate this through breath work and various means like religious experiences etc, I've done so myself. A strong psylocbin induced separation is far more intense by an almost incomprehensible order of magnitude.
For an example, let's say you induce a, for lack of a better term, trip from breath work. At no point is it going to get so intense that every aspect of your body and conscience forgets that you are doing the breathwork and you are unable to stop even when prompted by people such as EMT's and police. Physically ending the breathwork will bring the separation back. With Pyscolbin that's not true and the intensity only builds and you could be in this state of unrecoverable separation for 8+ hours. In the reverse, the deep feelings and insight from Psylocbin come in that decline after the peak where everything starts to become real again and your recognition of the world returns and you remember you ate mushrooms.
After that though it's quite reasonable to get that same feeling from any altered state of consciousness.
To me, it's similar to that early part of the trip where you get tired and feel like you want to take a nap, only to find that impossible upon closing your eyes and seeing the images dance around. Eventually that part of the trip ends as the energy builds.
do you get it particulary when you lie down or put your feet up?
That said, I was still shocked at how quickly and effectively it worked the first I used it and how reliably it worked despite whatever state I was in. No amount of meditation or breathing techniques have gotten me close, and I've never had a natural flashback.
I guess if we'd want to know for sure we'd need to test the light and sound technique with people who haven't used psilocybin before, then let them try psilocybin so they can compare the experience, and then let them try the light and sound machine again to see if anything changed in how "suggestive" they are to the experience. And compare against a light-and-sound machine only control group. I doubt we'll see that happen any time soon though.