It's not clear what can be swapped out. The Mac Airs supposedly didn't have user replaceable SSDs, but I easily changed mine from 64 GB to 180 GB. The SSDs plug into a socket on the Airs and no reason to believe that the Pro's will be different. The base RAM is soldered in place, so order the largest configuration of that that you can afford.
As to why DP would cover this, the computer is now the darkroom in the digital age. Questioning the inclusion would be like questioning why advances in enlargers were included in print photography mags in the 80's.
Having done a hands on yesterday with my 3 year old MBP side by side, I can tell you that, soft proofing on it will be so much easier and accurate. The glare control alone is a major plus. What kept me from springing for it yesterday wasn't the added cost of the display, it's the prohibitive cost of SSD storage: $500 US to go from 256 GB to 512 GB (still too small for me) was the deal breaker.
As more people get into digital photography, the market gets flooded with lowered expectations of what it should cost, as the bride who set off this thread so emotionally expressed.
There's room to carp with Nikki about this or that exact cost, but her point was, to make a living she has x in sunk and, x in ongoing costs, and a level of profit needed to make it worth it. Merlin Mann just did a great podcast called "The Hidden Cost is the True Cost" (http://5by5.tv/b2w/52). Worth it if you are trying to make a living making images.
The dilemma is that too many are vying to serve a shrinking customer base able to afford the true cost. And the irony is that established pros are finding it more lucrative to serve the growing ranks of amateurs/enthusiasts and pro-photographer wannabes than they can make off prints. When you can make more selling "How to Become a Pro" than you can off stock photography sales you know there has been a fundamental change in the business.