i'd wager it's either a hardware requirement (reusing existing components) to not have to build a different design prior to a full refresh with the new arch, or kind of a trial run for Apple to see how many would prefer a slightly cheaper design without the touchbar. The differences of the Pro vs Air are quite minimal. Where I do like the fanless design, I was concerned of thermal concerns on the Air, but there was no way that I'll ever buy a touchbar product from Apple ever again, so I took a shot with the Air. Pleasantly surprised with heat/energy/battery, and couldn't be happier to have the physical F key row back. M1 Air is hands down the best MacBook I've used since the 2015 MacBook Pro.