But if we leave the tablet/hybrid aside for a second and focus on full laptops. Honestly, the Air 13" profile is perfect for portability. why didn't Apple pursue it aggressively? why do we have an ancient line cMBP selling at the normal price point, and a current line rMBP selling at an overprice?
For Retina MacBook:
The Retina Display is actually quite costly. The screen alone probably costs Apple 2x to 3x the cost of a regular low resolution screen. Regardless of what form factor they stick it on, it'll drive the price of that line up proportionately by $100 to $200. And that's not to mention the extra components (more powerful processor, bigger battery) required to adequately drive such a display.
While the 13" Retina MacBook Pro costs quite a lot, there is not much room for Apple to wiggle if they want to keep the same profit margin as before. Dropping profit margin = bad business. Investors will chew Apple's executive heads for breakfast. Some of us may not think so, but Apple is a business, and like all businesses, it cares about profits more than about its customers. Customers are only a factor of the huge sum that adds up to profit.
Also in that same light, the 15" Retina MacBook Pro isn't overpriced at all... by any metric.
And if you still can't concede with this point, then try to find another laptop on the market with the same screens as the 13" rMBP or the 15" rMBP that's priced lower. If you can't find any, then the Retina MacBooks can't be overpriced since there is nothing to compare the pricing to.
For the Unibody MacBooks (I don't like cMBP because "classic MacBook" should be the silver non-unibody MacBooks from 2008 and prior):
They are still very good laptops that sell well. There is no reason for Apple to cut them off now or in the future.
If you have to make comparisons to MacBook Air:
MacBook Pro unibody actually has a stronger, more rigid body that does not bend easily. I have owned a 13" MacBook Air and the thing bent very easily. In fact, sometimes I was afraid I'd twist and snap the computer in half just by holding it.
The MacBook Pro unibody still has a much better screen than the MacBook Air where color reproduction is concerned. For some reason, Apple opted to include a worse panel in the MacBook Air even though it has higher resolution. As a result, the MacBook Air's screen looks sharper with its higher resolution, but it has less accurate and generally more washed out colors compared to the MacBook Pro.
MacBook Pro unibody's glass layer protects the screen very well against dust, scratch, and other factors. The MacBook Air, on the other hand, has only a thin plastic film on top of its display that barely protects the screen at all. It is very easy to scratch and damage the MacBook Air's display.
MacBook Pro unibody has better Thunderbolt throughput compared to MacBook Air:
http://www.anandtech.com/show/4542/eagle-ridge-the-cheaper-optionally-smaller-thunderbolt-controller
And etc...
There are many things the MacBook Pro unibody line does better than the MacBook Air, and vice versa. They are there to contrast and compare with one another, and I think that's precisely why Apple is keeping the unibody line around.
At the same time, the Retina MacBook line doesn't offer any of those trade-offs. Aside from storage capacity and legacy connectivity (optical drive, Firewire, Ethernet), the Retina MacBook line is simply better than the other two lines in every way.
So I think it makes for a good case:
do you want the light-weight Air, or the more durable Pro? Or do you want the much better Retina?