As I understand it, soft proofing allow one to see (more or less) what a print will look like on the paper, and according to Schewe you then put on an additional curve to bring the view of the print back to close to what you wanted in the first place.
The question is - why can't the program do most of this for you? - after all, it has the original image, and it has (via the soft proof) what the printer will produce, so can't it generate a curve to "fix" the result.
I suspect it's not that simple, but it it should be possible.
In Lightroom, maybe the "print curve" could be a separate function some how attached to the paper profile.
PS That title was meant to be " A question for all you printing experts"