Motorola started to cultivate a reputation for reliable and quick Android updates after the company was acquired by Google... then began to shoot itself in the foot following the Marshmallow release. It looks like the company is still interested in timely updates for its flagship phones, at least: Motorola Senior Director David Schuster told his Google+ followers that engineers have already begun testing Android 6.0 on the Moto X Pure Edition (that's the new Moto X Style if you live outside the US).
"There have been a couple reports of a Marshmallow "soak test" that has started for Moto X 2015 Pure Edition. Just want to make it clear that we have NOT started a formal "soak test". We have started a small TestDrive for the Marshmallow upgrade on Moto X 2015 Pure Edition. We will be conducting these tests for the next couple of weeks. Pending the feedback during this test cycle will determine the timing of a full soak test."
For the uninitiated, a "soak test" is Motorola's term for a private firmware beta test, usually limited to users on Motorola's support forums who are active and provide reliable feedback. These are semi-secret, but news often leaks out (occasionally including the firmware files themselves). Since Motorola likes to keep soak tests on the down low, it's not surprising that some limited rumors spun into a full soak test. Public rollouts usually follow those soak tests by 2-6 weeks.
Expect similar trickles of news for Motorola's other new devices, the Moto X Play (not available in the US) and third-gen Moto G, as well as the 2014 Moto X, Moto G, DROID Turbo, and Moto MAXX. New Motorola DROID phones for Verizon are expected to be announced on October 27th; coming so soon after the Marshmallow release, it's unlikely that they'll launch with Android 6.0.