Yes, but is there anything that enables them to make the cognitive leap from "my phone runs an old version of Android" to "my phone should have been updated to a new version of Android"?

What's to keep them from instead coming to the conclusion of "my phone is old, I should buy a new one"? You assume they understand what "Android" is, who creates Android, who creates their phone, and that the thing running on their phone that's called "Android" can be upgraded but the entity that created their phone prevents that from happening.

Many people are just buying a phone. Heck, many people are just getting a plan which happens to give them a free phone. They don't, and have no desire to, understand the nuances of the phone they just got. It makes calls, browses the internet, and may let them install these "app" things.

And what's to say some of the people who do understand some of these nuances don't erroneously blame Google and Android rather than their phone's manufacturer?

I really do bet most people out there just say "damn, my phone's old" and go try and buy a new phone as soon as they're able. Which is a win for companies like Motorola.