As for what I expect from a Nexus
What you expect and what is promised are not the same, in this case they are very different.
I demand a minimum of two, but find it reasonable to expect three.
So now it's an unrealistic demand you're making, and not their failure to keep a promise (they never actually made)?
From this, it seems clear that Google has completely lost its commitment to the Nexus-brand
Regardless of the circumstances, this is an absurd claim.
When you look at it that way, the Galaxy Nexus received one major update and that was it. That's less than most "flagship" consumer devices sold, which typically receive at least two.
As for what I expect from a Nexus, I demand a minimum of two, but find it reasonable to expect three. From this, it seems clear that Google has completely lost its commitment to the Nexus-brand, and to me that makes the Nexus-brand completely uninteresting.