Google has once again updated their support matrix for the Nexus and Pixel lineup of devices. Previously the company had outlined dates of when major updates and minor security updates would cease for the devices. There is nothing new here in that regard. What is new is the dates for the end of online and phone support for the devices. The good news, or at least the non-confusing news, is that online & phone support ends when security updates end on the devices.
Take the Nexus 6 for example. There are no guaranteed Android updates to the device since October 2016. No, Android O is not coming to the Nexus 6. Sorry, I loved it too. In October 2017, guaranteed security updates end and that is also when online and phone support ends for the device. Other devices follow this same timing.