Comment by eggy

Not even for all of the available shaders, books, tutorials and other resources made available for it over the years? The analogy I make is a programming language that is so-so, but has a hundred relevant, useful libraries vs. the technically better language with hardly any libraries. Cycles has the basic building blocks to create a library of pre-defined shaders, but Renderman has over 25 years of history, and tons of RSL examples.