The research university, but without teaching, is about as different from the research university as a horseless carriage is from a horse and carriage.
I disagree. The crux of the university - faculty mentoring junior researchers (aka phd students) remains in both setups (and in industry research labs). The undergrads at research universities seem to be lower on the priority list
Normal people think of the primary purpose of a university as educating undergraduates. If the only education going on in a research institute is apprenticeship as a researcher, possibly with some directly relevant technical courses this is so far from most people’s experience of a university as to be a different thing. Professional academics may disagree but if an institution goes from encompassing a broad section of society to a narrow one, from educating and doing research to doing research and education only as necessary to that and from providing a space for maturation and relaxation before adult life to being a professional workplace that’s a pretty drastic change.
A research university is a lot closer to a non research university than it is to a research institute.
Medical school faculty, especially in soft-money positions, might never set foot in a classroom. Some of them will even have labs that are almost entirely postdocs and technicians. This doesn't seem wildly different from a research institute to me. If anything, the funding is probably less stable too, since you're on your own.
