There are always at least two sides to every story.
I guess the point I am arguing is that I don't think responsive design makes you any more money than fixed design. If it did organizations such as eBay would have certainly made the move by now.
At some level --at least for me-- if it isn't going to generate more revenue it isn't worth the extra effort.
Clearly I don't have any data to back-up my claim so we'll have to leave it as conjecture at this point. I can't say either way. Just a hunch from observing what's going on with top-level sites both as a developer and a user.
I equate this to the whole 3D movie/3D TV fad. Yes, this is probably a bad analogy. The point is that 3D has always been a fad. It comes back every N years and everyone proclaims that "this is what it will take off". Film producers get all hot-and-bothered and jump on the 3D bandwagon and forget why people go to see movies: The story. A 1940's black and white movie with a great story will always do better than a new film with a bad story, no matter how much tech, 3D and special effects you throw at it.
I guess what I am saying is that content is far, far more significant than design gimmicks. Customers don't come to your site to be in awe of your engineering or design chops. Craigslist proved that point long ago. No, they come to your site for the value they may be able to derive from it. Good relevant content and great value are at the top of the list. Ease of use and security may be second. Beyond that, everything else is optional and, in my book, can only be justified if you can show that it can improve conversions relative to other approaches.
As I said before, one of the reasons I currently tend to reject the idea of responsive design is that it can create a situation where site optimization becomes a geometric problem. Now you have a dozen layouts per page to optimize vs maybe two. I've seen some really amazing optimization reports where things as simple as the position and size of elements have made a huge difference. I am not sure how you'd even begin to approach that with responsive design when you've introduced so many additional variables in to what --in the cased of fixed design-- was so simple.