I can't really speak for anyone but myself, but when I first started tripping, I never really noticed visuals until I first took a really heavy dose (then they got fucking WILD!)...since then I will get some visuals even if I'm underdosed. I think a lot of people with higher sensitivity just need to take more to be able to have visuals...
I also have known people who didn't even get visuals eating ten strips though, but in those cases they were the type of people who "close themselves off" mentally/emotionally from the world (not saying that's true of everyone who experiences psychedelics in that way just an observation of a couple people I've known)...the lack of visuals is like a metaphor for an inability to see a lot of the positive perspectives psychedelics can help you find & an inability to get beyond the "surface level" of the psychedelic experience.
But by that same token, the people I've known to have the most ridiculous, off the wall visuals, also don't seem to "get it", and also never get past that "surface level" of tripping & into the real, useful side. They never learn anything because they get too caught up in visual & sensory effects. This is just based off of a few people I know though, can't speak for all who get no visuals or insane visuals or those in the middle.
Lastly, I will say that personally, I've always gotten visuals for a long time, never any complete hallucinations (outside of DMT), at least not since I became more "used to" tripping, but very beautifully organized patterning, morphing, color alteration, etc, occasionally more bizarre things, which gets very intense up to a certain point, yet when I push the dosage really high visuals actually become less noticeable, definitely present & intense but I can't focus on them anymore & thus they don't get too crazy as they could at slightly lower (but still powerful) doses.