Interesting replies, thanks to each of you for sharing. Good to know I'm not alone

I should add, too, that I quit smoking marijuana about 5 months ago, completely unrelated to any intentions of set/setting for my trips - it was out of necessity for employment - and thus, I had no expectations whatsoever as to any difference that may or may not be caused.
The only other significant difference I noticed when reflecting on it since then is a dramatic reduction in anxiety/apprehension, particularly during the come-up phase when smoalking, but my anxiety levels dropped significantly at all times in life.
I had the thought after reading your reply, tatt, that perhaps the association of the fractal/geometric OEVs with the come-up phase, that being when the anxiety would be at it's worst, has something to do with it. I've made no other significant changes whatsoever to my usual set/setting/lifestyle, and to be perfectly honest, I would think heightened visual stimuli would come with having gone so long without a psychoactive drug (referring to the mary jane) that I'd been accustomed to for over two decades...
...and for the record, I have no disappointment at all in regard to the visual effects being greatly diminished. I don't expect them; I had simply become very much accustomed to them and was taken aback by the lack of them.
Gwn, I've been meaning to experiment with introducing music or some color of noise into my setting because I've had some intense, profound experiences when inadvertently having auditory stimuli in my setting. One time in particular, I experienced the audio in the background (a TV commercial) being sped-up with exponential acceleration like there was an ethereal finger on the lp of my setting spinning time faster to get to the breakthrough, at which point the background noise went poof, and then came back later right at the point where it had been in the commercial before being sped up

I typically rely on intuition to guide me when it comes to timing, set, and setting - which is far more often than not my quiet room lit only by the moon - and am well-practiced in having no expectations or impediments to thought. The emotional intensity has not diminished in the slightest, so the experiences are most definitely not being pushed away.
From what I've gathered of my own thoughts prior to starting this thread, I would agree with your assessment, Jees, in that in all likelihood, the phenomena is ado with visual and auditory representations that have become unnecessary over time.