Napster was a bad implementation at the right time.
RoR - credit should be given. Sometimes just getting off your duff and starting something is what the world needs. Motivating many others to refine code into something useful deserves credit.
(EDIT: I am not saying anything was/wasn't a work of genius. I'm just saying it's truly creditable, whatever it was.)
I definitely agree with you on Napster. I am less sure about RoR. It was a a very nice improvement over existing systems, but how much of that was DHH genius and how much was simply due to Ruby providing a better platform upon which to build this particular framework I do not know. It was definitely better than existing alternatives in other scripting languages, but I was not a part of the Ruby world at the time and have no idea where the initial RoR work fit in to the whole Ruby ecosystem at the time.
Why do some people/code get attention and accolades, while others, equally deserving, do not? Timing? Personality? Bluster?
Nitro, another MVC-ish Ruby Web framework released at the same time as Rails, always stuck me as being a much better approach to the same problem, and better engineered (thread safe, less "magic" and munging of core Ruby classes, a form of pipeline transformations somewhat similar to Rack middleware today), but for whatever reasons Rails managed to capture far more attention.
The big win for Rails was not the initial code itself, but in capturing attention and motivating people to contribute, to fix it up, and make it better.