"I you have a good profile, both the print and the softproof should look as much like the on-screen image as the printer's/paper's gamut will allow."
Ole, you answered your own question, but you may not have realized it. "as the printer's/paper's gamut will allow" is the key phrase in your post.
If the print is your final output, you have to use soft-proofing to let you see a close approximation of what will actually come out of your printer. Then you can make final adjustments to your image to optimize for what the printer/paper combination can actually produce. With today's technology, the printer/paper combination is the weakest link in the chain, if you don't soft-proof you're playing against the house. You may luck out occasionally but, over time, the house always wins.
You won't be able to nail it down absolutely, there's a big difference in the emissive image you see on your monitor and the reflective image you get from the print. But soft-proofing will get the two a lot closer than just shooting in the dark. And, given the cost of ink and paper, that's a "Good Thing".