A product is designed to solve an end user's problem, so it should be fit for an end user to use.
This is development.

A prototype can be useful in figuring out how to solve a developer's problem, so it merely has to work well enough to prove some concept.
This is research.

I am saying that there is a difference between R&D.  

 There is value in solving made-up problems, in order to have a use case for implementing a concept. It doesn't have to ever be put to use, to have value. 

 I meant product is for user problems, we are saying the same thing