The problem is that I don't see Apple going downmarket with the Mac. If it's a cheaper Mac you want, that's the iPad.He certainly hasn't got any intel on final pricing but he probably has excellent intel on the BoM, on the new MB and on older ones, so he can easily map all of Apple's historical profit margins.
So he can probably make an excellent guess on final pricing.
All trends point towards the Mac becoming even more expensive, not less. It's more likely we see a refreshed 13" Macbook at an even higher starting price (say ~$1199), though it's anyone's guess if it replaces the existing 12" Macbook or if the 12" macbook receives a price drop and becomes the new entry level laptop.
In terms of specs, the MBA simply has no place to exist today. It's thicker and heavier than the Macbook, and doesn't have any USB-C port.