I'm guessing the MacBook (minus Air or Pro) will simply fade away -- or perhaps be rebranded as a smaller-display Air (hopefully not MacBook Air mini...)
"If you just stop to think about it, it makes almost no sense that both the MacBook and this new MacBook Air now exist. Previously, the MacBook Air was the low-cost Apple laptop, starting at $999. Now it’s up to $1199 — just $100 cheaper than the MacBook. A device which is smaller and lighter than the MacBook Air. I know I’m overthinking this: Apple has a winning brand in the MacBook Air, so they wanted to make a new one, knowing it would sell. But the branding makes no sense.²Apple’s Aim to Please Event | 500ish Words
Again, this shouldn’t ultimately matter — certainly not for the new Air. But it’s hard to see who buys the MacBook now. If you prefer just a slightly smaller device and/or screen? Or if you want fewer ports? Or don’t want TouchID?³ Want worse battery life? Hate recycling?⁴ Perhaps it’s slightly faster — there’s oddly only one processor choice for the new Air — but that’s impossible to know before the benchmarks.
We’ll see what they do with the MacBook next year. It’s clear that the line should be whittled to a MacBook (consumer) and a MacBook Pro (professional) duopoly, but instead we have something more like: MacBook Air (consumer), MacBook (prosumer?), and MacBook Pro (professional)?⁵ Again, it’s a muddled message that will undoubtedly hurt the MacBook."