“It sounds wild, but the A10 looks to have the power and efficiency to handle the workload of a full PC. […] Intel already let Apple down once with the original MacBook’s underpowered Core M processor, and the absence of an Intel Skylake upgrade for either the MacBook Pro or Air this year also seems to have been caused by Apple’s dissatisfaction with Intel’s CPUs.”

- Vlad Savov for The Verge

Probably an uninspired bet: within 2 years macOS will be running ARM and on ARM-based MacBooks. Even tough Intel now owns a license to produce ARM chips, they might be late to the race. Also not a surprise, Apple wants to control its components and their manufacturer.