When I wrote the $5000. per print I was stating an ideal scenario, perhaps being flippant.
None of us usually have clients like that but it was meant to state that we should perhaps be more in charge of our business and have creative ideas in marketing and not just stick with the ideas that have been used for years. The public doesn't know much about any of this and if they want our work, they will generally be willing to pay what we ask, within reason.
As for the collaboration with the client on conceptionalizing the image, I think we all do that before the sitting to a certain extent.
Also as Cheryl stated we generally do fairly standard fare initially and then branch off into more creative ideas. This also gives us, and the person being photographed time to warm up to each other and get used to each others rhythm.