But I never refer to the product as Echo. I refer to it as Alexa, because no one who comes to my house knows what an Echo is. So, when I refer to it in conversation, I call it "the A-word" (not kidding)
I think this is the key difference between it and the iPhone: Siri is one of the ways that people interact with an iPhone, not the only. In fact, Siri is probably a minority means to use an iPhone. (I know it is not for me.)
But Alexa is the way people will interact with Echo, after setting it up. So it makes less sense to keep the two ideas separate.
