The recent Apple event in New York City had a lot going on, and we’re still working through all the new products the company showed off. But as the dust clears, there’s one lasting impression about which I feel remarkably certain.

There’s a sea change coming.

John Gruber alluded to this in his piece at Daring Fireball about the new MacBook Air:

Look at the iPad’s A12X compared to the iPhone’s A12 and you can see how much attention Apple is paying to the iPad’s system architecture. There’s no reason they won’t pay as much or more attention to the Mac’s custom silicon when they switch from Intel to their own chip designs. It should be downright glorious.

That line in the middle, delivered in a matter-of-the-fact fashion, has stuck with me. Not “if they switch.” “When.”

Like many other Apple watchers, I’m considering this transition a foregone conclusion. I’ve already put a stake in the ground that Apple will ship a Mac with custom silicon by 2020 at the absolute latest, and I stand by that.

The question is: which Mac goes first? There are, to my mind, two major contenders in this space.

Rewriting the MacBook

The addition of the MacBook Air threw Apple’s laptop line-up into even more disarray. We now have the 12-inch MacBook, the 13-inch MacBook Air, and the 13-inch MacBook Pro (sans Touch Bar), in addition to the remaining MacBook Pro options.

It’s especially hard to see how the MacBook fits into this line-up. It’s $100 more than the MacBook Air, and doesn’t pack quite the same bang for its buck. (Granted, if you’re looking for thin and light, it still manages to beat out the Air on both those fronts.) Sure seems like the MacBook is due for a refresh, though…and what if that refresh were to headline a transition to an Apple-designed chip?