Sure. And in the case of the 15" rMBP the retina display commands a price of negative $200 compared to the similarly spec'd cMBP. That's a fact.
Your theories are reasonable, and I'm not claiming my view is definitely the right one. It just seems weird to rely on theories when we have evidence of how Apple is already pricing the retina 15" relative to its non-retina sibling.
You theory is flawed. It isn't relevant evidence. The facts are that rMBP 15" was slotted into the top of the Mac laptop price range and killed off the MBP 17". It was slotted into empty price range.
The rMBP 13" is being slotted into the middle of a price range for laptops. There is zero rational reason to use the same tactics in those two extremely different contexts. The cannibalization impact going to the middle is going to be extremely more sensitive to pricing.
As Apple products get lower the pricing tends to be much tighter. There is a $300 gap between MBP 13" and 15". A $400 gap between MBP 15" and rMBP 15".
The gap for the 13" is going to be higher for two reasons. One the SSD versus HDD. Two, soldered RAM probably it is going to be an 4 versus 8 issue between the two. Couple a substantially higher cost display ( laminated/fused and Retina ) along with increased battery component costs and it is an "apples to oranges" comparison. The specs
are different. It is not the BTO pricing that is the primary issue. It is the non-BTO pricing. Delving into the BTO component pricing is just plain misdirection away from the core issue.
Taking the higher component costs and tacking on Apple's usual 30% mark up on non-BTO devices and that will provide a closer track into where the costs are likely to be.
In contrast, at the high end of the price range you are primarily dealing with the most price insensitive users so the the "gouge" can pull off on BTO components is higher, but these insensitive folks are much fewer in number. So they cannot push the base prices for a 15", even with 'Retina' , far over the $2199 level (or even start at the 17" $2499 point.... which was really viable in 2012 anyway). That's why they slotted into the old 17" price range.
Furthermore, Apple has already used $1699-1799 price range for a 13" laptop before during the first couple of years of the MBA. Just like the 're-use' of the MBP 17" range these are sitting there open. If your "evidence" is what Apple has done in the past ... they have done almost exactly this before.
Apple is more likely going to price this under the MBP 15" ( $1799 entry point ) and above the top of the 13" entry point ($1499 top point ). That leaves $1599 and $1699 as the possibilities. If they go with a large SSD and 8GB 'standard' then the $1699 is the far more likely price point.
It will be a new product between the legacy 13" offerings and the legacy 15" offering.