The 2015 Macbook is certainly not a product that could replace my productivity notebook. With only a single connector for power and connectivity it utterly disqualifies for my usage scenario where 3 USB ports, a single external screen connector and a single Ethernet port I have on my current notebook is often not enough. But while that is so that device is a first of its kind because it's a product that bridges the gap between smartphones/tablets on the one side and notebooks/PCs on the other.
Have a look at the iFixit tear down and you see what I mean. The motherboard is only slightly bigger than what you find in a tablet today and certainly doesn't look like a traditional notebook motherboard anymore. But the whole setup is strong enough to run a "full" operating system and not a stripped down version such as Android or iOS. If the screen was touch sensitive that device would actually be a tablet with a built in keyboard with a full desktop operating system rather than a notebook.
So what began in the mobile space when the Linux/BSD kernel replaced operating systems that were developed far away from the desktop world in 2007/2008 with the first Android and iOS devices has now extended to the overall operating system itself.