I think Apple is catering to market segments. The Pro market. The one port/business/small/quiet/shiny market. The el cheapo market. They've got a foot in each because the Pro market expects to spend $2k on a laptop, the MB market will pay anything for these features, and the people who have a mental block beyond 999$. The cost of MBA parts isn't gonna decrease over time as the Broadwell processor becomes a scarce product so they're forced to upgrade. I think Apple is afraid to kill the MBA completely due to said 999$ mental block for many people so hedge their bets to see what sticks. This is Apple's way post-Steve as they're not sure.
Apple is definitely catering to market segments. Not unlike the way they segment desktops: $499-1,999 for Mac mini, $1,099-5,299 for iMac, $2,999-6,999 for Mac Pro and $4,999-13,199 for iMac Pro. Business/professionals buy all four models; consumers rarely buy the desktop Pro models.
The laptop line is interesting because it’s the product line with the highest minimum. With iPhones, $349 gets you the budget SE. With desktops, you can spend only $499 for the budget Mac mini. But with laptops, you’ve got to spend at least $999 for the budget MacBook Air. Of course, you can also spend as much as $6,699, in overlapping price bands:
$999-$1,549 MacBook Air
$1,299-$1,949 MacBook
$1,299-$2,599 13” dual-core MBP
$1,799-$3,699 13” quad-core MBP
$2,399-$6,699 15” hexa-core MBP
At $999, you’ve only got one choice. But at $1,500, 2,000 and 2,500, you’ve got your choice of three models, at three basic configuration points:
$1,500: top of the MBA, middle of the MacBook, entry level dual-core MBP
$2,000: top of the MacBook, middle of the dual-core MBP, entry level quad-core MBP
$2,500 top of the dual-core MBP, middle of the quad-core MBP, entry level hexa-core MBP
But these price segmentations aren’t what separates pros from consumer. You’ve got consumers buying relatively expensive MBP, and you’ve got companies that spec the MBA.
Businesses buy the Air because it’s the least expensive laptop that still gives their pros (esp. those who travel) what they want and need: a small, thin, light, quiet, long-lasting, reliable and well-made laptop, that’s powerful enough to get the job done. Of course, being the lowest-priced laptop the Air is also popular with students and those with a limited budget, where price is the main consideration.
The Air is a huge seller because it’s Apple’s least expensive model, and they’re quite aware of that. However, they’re not afraid to kill the Air. Rest assured that the Air’s replacement will also hit that $999 price point, though, so you really don’t need to be concerned about Apple’s sales. They’ll surely continue selling millions of $999 laptops, and 10-12 million more expensive ones as well.