This way of writing confounds the traditional definition of authorship. I would be the Information Architect for the project, the film equivalent of the "director." The publisher (or supporting agency, whether a university or publishing house or whatever) would be supporting the equivalent of a movie cast and crew: a dozen or more writers who would write 200-word blurbs about different kinds of writing from every conceivable angle, which would be compiled into a huge database of writing instruction tips — the "text" of the textbook.