I think you are wrong. Ideas are a dime a dozen, good ideas are not. Ideas, which can be put into something useful. Yes, bringing an idea to life is also important, and often credit belongs to the person who does. But on the other side, there are plenty ideas, which once being had, are trivial to put into production.

So credit belongs to all involved people. Sometimes it is more the execution, sometimes it is the idea by itself. And very often, it is a process of iteration. Having an idea, implementing it, augmenting the idea and implement that.