re: Will AT&T Nexus 6 ever receive Android 6.0 Marshmallow? Update: YES!
I bought my Nexus 6 from Amazon not AT&T. My updates come from Google not a carrier. But there has been no explanation from Google why the Nexus 6 hasn't received even Marshmallow 6, let alone 6.0.1.
I can tell you Google did fix this -- With the 6P they do not allow the US carriers to sell them and therefore they do not need them for anything. When an update comes out -- I get it from Google within a few days (they do it in batches) -- no wait for any carrier.
I bought my Nexus 6 from Amazon not AT&T. My updates come from Google not a carrier. But there has been no explanation from Google why the Nexus 6 hasn't received even Marshmallow 6, let alone 6.0.1.