Most formulators know this in theory. Foam doesn't equal clean(s)ing power. A surfactant can cleanse perfectly well without producing a dramatic lather, and some of the harshest surfactants make the most impressive foam.
But here's the honest question: do you actually believe it when you're the one using the product?
I ask because I notice it in myself sometimes. I'll test a gentle cleanser bar that I know is working at a good surfactant percentage, pH is right, micelle formation is fine, and everything checks out. And yet if the lather isn't satisfying, there's a small part of my brain that questions whether it really cleanses.
It's consumer psychology working on the formulator. We're not immune to it.
Quick poll — when you use a low-lather cleanser, do you:
Tell me in the comments, too. I'm genuinely curious whether this changes with experience level.