I've never been persuaded by Rosen's account of that repeat. Most accomplished pianists are plenty bright and have read their Rosen, but don't necessarily agree with everything he has to say. (His preference for the early Schumann editions, for instance.)
I've formatted ~100 non-scientific books with LaTeX, including poetry and experimental/avant-garde fiction that makes considerable layout demands. I have yet to run into a problem that could not be solved. It isn't always the best tool for the job — for layouts with lots of images that need to be precisely placed with text, something like Affinity Publisher or InDesign would be a shorter path to the right result — but it's an amazing and remarkably painless system. If you are producing "incredibly inelegant bloat code" with it, I'd hazard that something other than LaTeX itself is responsible.
It is indeed in The Tao Is Silent — Raymond's first popular book and one of his best. There's a recent reading of the dialogue on YouTube by Curt Jaimungal, on the "Theory of Everything" channel: https://youtu.be/P-jh6tRh3Jw