I would have to disagree with you, because if Apple actually introduces an updated MacBook Air (let's call it that for lack of a confirmed name) and they have decided that it is (finally) time put a Retina display in the Air, to me that signifies a big change in thinking on their part, which I think carries over to the CPU as well. The other pieces (ports, keyboard, design, size of screen) are all important, but consequential as there is already precedent in the MacBook Pros from 2016 onward and the prior MBA. Pricing is the sticky wicket in this equation. Profit rules, marketshare is not being fought over in this space, so is the mindshare worth less gross margin? Seven years of Tim Cook as CEO would point to a big, fat NO, but I digress.
On the Windows side, users have had quad-core 15w Core i5 and i7 CPUs available to them for just over a year. Quad-core CPUs at the same price point as dual-core is now the norm in that world. This is reinforced by the fact that Intel has exactly one dual-core i5 and i7 in their 8th Generation lineup and those are the Y-Series that just got introduced a few days ago. I just cannot see a 13" MacBook Air with a Y-Series CPU, I cannot see putting in a 7th-Gen Kaby Lake (PR $#!tshow) and I cannot see a Core i3-8145U instead as the Core i5-8265U RCP is only $16.00 more ($281.00 versus $297.00). I know Apple doesn't pay those prices, but the delta in pricing between the i3 and the i5 is tiny.
I believe the $1099 21.5" iMac exists only to sell into the education market at this point, since the Mac mini requires a KB, mouse and display, it is messy and it is 4 years old versus the iMac, which provides decent power (better than the prior 1.4GHz version and the current mini) at a decent price (esp. in bulk) and one cable (power cord). I do not think it should be used as an analogue to the MacBook Air versus MacBook Pro pricing, but that is my opinion.
Remember, once upon a time, the MacBook Air was THE best-selling computer Apple made (2010 up until 2015) and it received updates annually from 2008 to 2015. When Apple stopped updating it in 2015, that solidified my opinion that the 12" MacBook was there to replace the Air. But it didn't...I am sure it sells, but it just is not an Air, the Air. People are weird that way and I think Apple misjudged what the response would be in this case. The fact that they still sell a 2017 MacBook Air that was tweaked in the most infinitesimal way possible leads me to that conclusion.
Had Apple not introduced the 12" MacBook, I do not believe we would even be having this conversation. Instead we would be waiting for the Late 2018 MacBook Air to be introduced during a keynote in which Apple would be touting that "the MacBook Air continues to be our best selling computer, but now it is time to replace the 2017 Macbook Air with the "best" MacBook Air Apple has ever made (duh!). Well, we had to decide what to do for an encore after we added that gorgeous Retina display to the Air in 2016...and we turned our thoughts inward and decided it was time to give the little laptop that could a bigger engine, a bigger display and an updated design. So, we've put together a little movie we would like to show you." Cue Jony Ive!
I think they will keep the MacBook Air name as well. I know Macs are now a very small share of Apple's profits, but there is no reason marketshare, sales and profits cannot all go up with just a bit of time and attention on Apple's part. I love the iPad, but I cannot do my job with it. Students and everyday users want a smaller, lightweight, affordable laptop. Aspiring developers with tight wallets (or no wallets, but a supportive parent) and an idea need something more affordable than a 13" MacBook Pro and until Xcode come to the iPad, they need a Mac that embodies certain attributes...that is the MacBook Air.
But, hey, First World Problems!
I think the MacBook was, and still is supposed to replace the MBA. However, Apple was too quick to release the MacBook. It’s design and low-power processors make it a non-starter for most people who want a main laptop, couple that in with its high price-point and it’s easy to see why it has been unable to have the success of the MBA.
If what we think we know about the future of CPU architecture is correct, then the MB could finally have enough to be a principle computer starting in 2020/2021. Until then, it’s a great companion laptop, especially for those of us who travel often.