If they plan to sell any volume, they can't rely on leftovers.
Unless the "leftovers" in question are "leverover capacity on the previous process node that doesn't have pricing competition, so Apple's able to continue to demand all of the supply at their desired price point"
What counts as "meaningful volume" is probably very different for laptops than for smartphones.
Unless the "leftovers" in question are "leverover capacity on the previous process node that doesn't have pricing competition, so Apple's able to continue to demand all of the supply at their desired price point"