Especially since there's not much effort from Apple needed to keep the Mac lineup modernized. Intel does much of the work for them.
Apple could just drop new Intel chips into their existing MacBooks as they get released, and easily be getting improved speed + efficiency each year. The new Kaby Lake chips even do hardware 4K video and VP9. http://arstechnica.com/gadgets/2016/08/intel-unveils-kaby-la...
sigh