That explains things a bit

It's Apple's fault that the Nexus 6 doesn't have a fingerprint sensor (The Verge)

Former Motorola CEO Dennis Woodside has confessed that the dimple at the back of the Nexus 6 was originally intended to play host to a fingerprint sensor. Back in 2011, Motorola was a pioneer in bringing fingerprint recognition to its Atrix 4G smartphone, however the company it used then, Authentec, was purchased by Apple a year later for a price of $356 million. Authentec were, in Woodside's judgment, the best supplier around and "the second best supplier was the only one available to everyone else in the industry and they weren’t there yet."