... In many ways, the 13" Air beats the 13" cMBP in normal speed tests due to the SSD, and they now cost the same at base configuration. Non-Retina MacBook Pros are gone. The fact that the two revs shared a single rev side-by-side is uncommon and, for those of us who really wanted/needed one, a blessing.
They're not gone and they are side by side because more folks were buying them than any other Mac model. Apple couldn't risk nuking them in one step because if the wrong move that would practically blow up the whole Mac market. ( Mac market saddled with the same 'doom and gloom' that the general classic PC market is laboring under would be worse for the Mac than it is for the broader market. )
It is purely an artificial impediment that Apple makes the Apple labeled 2.5" SDD prices so disconnected from the real 2.5" SSD market. a cMBP with an ODD dropped to offset move to standard form factor SSD would work.
Unless display thickness is an issue, I don't see why it couldn't get a retina display.
For the MBA ? Pricing. A Retina display would be lower margins if the prices stay the same. The MBA gained Mac share because of the lower pricing. Back when it was more expensive than the MBP 13" it sold in dismally small (like Mac Pro sized ) numbers.
Also to a less extent graphics. MBA's are clocked slower on CPU clock but the graphics clock is cut even more so to dump TDP.
Apple has never done what they're doing with the MacBook Pro line with any other device. Period.
this is closer to being a architecture transition 68K->PPC and to less extent PPC -> Intel where there is some overlaps for approximately a year or so.
Similarly, the 15" rMBP is cheaper than the 15" cMBP when both are configured with SSDs, so there goes your "cheaper" argument, save for how the models are priced.
Only cheaper if use Apple components. Apple's totally disconnected from market realities 2.5 SSD pricing makes this an Apple to Oranges comparison. Use non-Apple RAM and SSD to "equate" the two and the cMBP 15" will come out less expensive. It is only if drink Apple kool-aid is the rMBP as "price leader" when it comes to leveling the RAM+SSD playing field.
Given Apple's stance on a HDD/ODD-less future for notebooks, I think they're fine sacrificing the low-cost of their non-retina counterparts, especially given that the 13" MacBook Air is poised to cannibalize the 13" cMBP.
If Apple bumps the MBA 13' RAM and SSD sizes to 8GB and minimal 128GB SSD while keeping the prices the same there is a decent chance they may nuke the cMBP 13" even though it probably is still selling in greater numbers right now.
It depends though if the MBA 13" and MBP 13" both grew or not. If both grew in sales numbers in 2012-2013 it would be huge bonehead move to kill one of them. If cMBP 13" is ahead but sinking steady due to MBA 13" pressure then yeah Apple probably would nuke it before it went too negative and impact overall Mac market growth.
Frankly, Apple's 13" laptop line up being capped at 8GB max RAM seems likely to present as a growth problem if the go that route. The farce they are playing on 2.5" SSD pricing is also increasingly a larger risk of the strategy failing.
Really, there's a rule in Mac Consulting...or at least there should be. Most of Apple's products are on an 8-10 month release cycle.
It is far more a 12 month cycle or more accurately a "once a year" cycle. Really 12 +/- 2-3 months. The plus/minus thrown in to dispel complete complacency and predictability (i.e., offset Osborne Effect) .
There are some subset of products that are consistantly not on that cycle though. Peripherals ( displays, routers, AppleTV ). Mini's and Mac Pro's have highly deviated. What Apple's competitors and part suppliers are doing plays a role also.
Then from months six to eight, it's "buy only if you need it".
Simple as that.
Actually that should be dominate default rule of them. Buy it if you need (represents significantly added value over what leveraging now. Not that it is newer or slicker. ). If folks buy every 3-5 years then the short term delta isn't usually a trigger.
Trying to "game" Apple by timing the buys is dubious and flawed strategy.
If generally need a Holiday Season gift ... buy late Nov -Early Dec.... but that is timed on when need the present, not gaming Apple. If workload has grown too large/heavy for current Mac get a new one.
Otherwise just wait till Apple announces. Then wait another 4 weeks until the release bugs surface and then buy based on better knowledge now have. in short , the other primary rule of thumb should be to judge buys on what you already know about the new products. Not guessing at unknown products.