Surely the cost to Apple of A-series vs M-series isn't that significant though? I'd think they'd need to cut a lot (or their margin) to get down to that price point on a laptop.
I would expect to see them use the same sort of game plan for an A series MacBook that they used with the iPhone SE.
Use previous gen parts for items like the screen and body (for cost savings) along with current gen SOCs.
With all of Apple's service offerings these days, they could also potentially justify slim margins by positioning the A-series MacBook as both a loss leader and gateway drug.
Apple TV 4K at 200, MacBook at 600
Back of the napkin math but it checks out.