I think the key difference isn't the memory, but the recall. Humans can recall memories at will, while dogs often require a prompt or stimulus, and there's not a clear indication that they're self-recalling information to think about things beyond a period of persistence.
That's not diminutive of them, more a reflection that we've been selecting dogs for this behavior and other "breed traits" (which I think of as specific hereditary OCD) for thousands of years, so it makes sense they're primed for this from a context- or direction-giver.
It's why if you teach a dog a trick that it's still able to recall years later, it won't go off and practice it on its own or teach it to other dogs.
That's not diminutive of them, more a reflection that we've been selecting dogs for this behavior and other "breed traits" (which I think of as specific hereditary OCD) for thousands of years, so it makes sense they're primed for this from a context- or direction-giver.
It's why if you teach a dog a trick that it's still able to recall years later, it won't go off and practice it on its own or teach it to other dogs.