I'd love to see some cheap ARM Mac devices, either a MacBook Air or Mac Mini. There's a lot of room for downward movement on prices considering they're no longer buying the much more expensive Intel chips. If Apple can sell an Apple TV for $200, I don't see why a hypothetical ARM Mac Mini with an A14 derivative and more storage and RAM couldn't be $400 or thereabouts.
I doubt that's how it will work out, but would love if it did.
For one, an Apple TV is much more of a "single-tasking" device like the early iPhones. You generally run one app at a time, maybe have a few background downloads. So Apple can use a much less powerful CPU (or even leftover A5 phone CPUs with a bum core, like they did for the AppleTV 3), and more importantly much less RAM (as they don't
have to keep several apps loaded). Also, permanent storage can be much smaller (1/4th of the minimum Macs come with these days), as the general idea is that it's mainly a cache, not a hard disk for offline use.
So basically, an AppleTV is closer to a "thin client" than a full PC. If you buy an Intel NUC, it starts in roughly the same price range as an Apple TV.
So I think the price savings is in being able to sell what is in some ways an iPhone 1 but leaving away the expensive battery, GPS, Wifi and touch display you'd pay for in that, as well as keeping the small storage (compared to a Mac), RAM and other things, which Apple mostly don't make themselves, and at best get a good deal on because they're such a huge customer.
The savings is likely
not that Intel charges Apple more for a CPU than it would cost Apple to make themselves. At best, there might be some synergy now where Apple can amortize the cost of developing a CPU across high-end phones and low-end Macs. So maybe the iPhone (being the better seller) can "subsidize" Macs. OTOH, margins on Macs are probably higher, so that might just end up going the opposite way: High-end Mac CPUs' power draw being reduced a few years later for the next generation of phones.