Apple's margins have typically been in the low 40% range. for a $1000 laptop, their all-in (includes shipping. warehousing, etc.) cost is $600. Of that $200 is Intel CPU, with about $50 for the support chipset from Intel, so Intel makes up $250 of the $600, leaving $350 in non-Intel costs, and $20 for the 16GB of RAM. Lets be generous and say that the Apple SoC costs $100 (includes the 16GB of RAM, replaces Intel CPU and chipset). This makes the cost now $430. At $750 selling price, they can maintain their 40% profit margin with the AS SoC. At $860, they can make a 50% profit margin.
However, this doesn't take into account a number of things. The Apple SoC will include other things that are on the logic board of the Intel laptops, like the T2 chip, like a lot of glue logic, passive components that go between ICs, etc., but are hard to put a value on. Those costs are very real, and will be taken off the logic board, but it is hard to pin the value. I would think there is probably $10-$15 for those components. There will also be a reduction in logic board manufacturing cost, as there will be a reduction in manufacturing costs (it takes less time to assemble a board with fewer components, even for the massive SMD pick and place machines). The total savings would be on the order of $17-$20 combined for the reduced parts count and manufacting time reduction. With all of this taken into consideration, at 40% margin, you are looking at a $720 unit, or $820 at 50% margin.
I can easily see the entry level Mac being sold at $799-$899, even with 16GB of base RAM.
Also, Apple doesn't make Macs: FoxCon does. Apple just orders whatever quantity they need, and its up to FoxCon to deliver. If Apple wants more Macs, they order more Macs from FoxCon, and it is up to FoxCon to figure out how to deliver them. If there are no supply issues (AS SoCs, flash or RAM modules, etc.) and Apple respects Foxcon's lead times, system volume is not going to be an issue. I am using Foxcon as a stand in for any contract manufacturer that Apple has a relationship wiith. It is also possible that Apple could bring on a second contract manufacturer if needed.