Look at the iPad Pro, 2GB of memory, not a "laptop" class CPU. etc. It is eating into Microsoft's market for the same reason. The "big" part of the laptop wedge is people who aren't gamers, or intense multitaskers, or intense local storage users. They are people who have their stuff in the cloud, want an easy to carry package that can run the apps they need to run one, or perhaps two, at a time.
The Chromebook is anticipating the iOS based, ARM processor based Macbook air. This is also the Surface Go space.