I guess I'll just quit asking BikeForums about nuances of bike component design. With the huge knowledge base here, I was hoping someone would have a story like, "oh yeah, Shimano tried that design just before cantilever brakes fell out of favor; it was a better design for these reasons, but it never was popularized because of its timing coincident with linear pull brakes", or "Shimano tried to re-invent the wheel with those, but they were harder to adjust or they didn't become popular for these reasons", or ... ... ...

Apparently, I shall be satisfied with the elementary knowledge that the fiction of the pad rubbing the rim stops the bike and anything more nuanced than that is not worthy of discussion.