Apple does not have Lightning on any Macs, and never will most likely.
Nobody wants to continue down this path of multiple cable types for different devices, and Apple has to see that the same charger for their new Macbook is the most sensible and convenient method to charge the accessories. As I've already pointed out, Apple is behind USB-C.
I never said Apple currently has Lightning on any Macs, but they sure do on the Mac peripherals.
When you say Macs will never have Lightning, do you really think that if Apple drops the 3.5mm Jack from the iPhone, with which they likely will give away a free set of Lightning headphones, that they will have no way to make them natively compatible with their other products without an adapter? Nothing would kill Apple's effort faster than the customer who buys a new MacBook and iPhone together, along with a new Lightning set of Beats headphones that require a USB-C adapter to use on a MacBook.
You go on to make a specific point about Apple making the chargers the same for their MacBooks and accessories for sensible convenience. But wouldn't it be most sensible if a person could use the same charger for everything, without having a bunch of different cables to accomodate Lightning and USB-C? Since Lightning seems to be Apple's choice of charging port for most of its current products, and it may be the future of wired audio delivery for their most popular device, it seems pretty likely Lightning will be added to the Mac if the 3.5mm Jack is removed from the iPhone (and even if it isn't).
The retina MacBook benifits the most of all, with room for only its single USB-C port and a 3.5mm audio jack. By switching that 3.5mm Jack to a Lightning port, it gains a redundant power and data port, allowing more common data items to be plugged into USB-C while simultaneously powered by Lightning.
There's also an argument that Apple could streamline its dongle/adapter collection. While Apple makes a lot of money selling multiple dongles to the same customer, they will likely make more by unifying them all to the same connector type -- I.e. Lightning.