I feel you may be looking at this through too narrow of a lens since it's not just about lines of code, though that's one part of it. I think the point is that

I feel you may be looking at this through too narrow of a lens since it's not just about lines of code, though that's one part of it. I think the point is that a 13 inch Retina screen can fit more "stuff" than a 14 inch non-Retina FHD/WQHD screen.