Yes, it's a significant expense even on top of an Apple salary.

Any company, not just Apple, should be tracking whether the extra spending is worth it. There must be a point of diminishing returns where additional AI usage stops increasing productivity at a comparable rate. That point should be your target. Different teams can have vastly different thresholds.

Companies also can't justify ever-increasing costs just because it increases productivity. It's business. You care about profits, not raw productivity. And Apple doesn't seem to be having a particularly great time these days.