Gone and soon forgotten

My daughter's hamster died this week. That isn't the bad part of this story. The horrible thing is that we didn't even notice for about three days, and what's even worse is that she hasn't noticed at all, even though the cage has been gone from the house for a week!
I was the keeper of the annoying critter, which means I changed the bedding, food, and water periodically. It ran on the wheel at all hours of the night on a journey to nowhere, such a depressing existence indeed.
The water and food was at a consistent level for a few days and I thought how quiet the nights had been when, before work one morning, I took a peek at the "sleeping" rodent. "Hmmm," I thought to myself, "No time to deal with it right now."
I left it there for the day and, when I got home, my son was standing by the cage. I pointed and said, "D. E. A. D." I knew his sister wouldn't hear or bother to decipher the word.
He said, "I know, Mom! I discovered it last night. I poked it with the fly swatter and it didn't move."
"Do not say anything to her about this! Do you understand me?" I was using my most threatening voice. "I just need some time to think about how to deal with it and get with Daddy on what we want to tell her."
She is 7 years old, after all. We fully expected tears or at least some sort of acknowledgement, but instead we said nothing, dumped the cage, put the fruit basket where the cage used to be, and she got a banana from there today, touching the air where the hamster used to endlessly run on that stupid, creaky wheel.
Nothing. Not one single word.
I realize how awful we are in our apathy of the deceased hamster, but none of us were very attached to it in the first place.
My son had a hamster named Peanut and I believe every one of us cried when she died. She had personality and, as we all know, personality goes a long way. Also, you could actually hold Peanut.
This new hamster was like a lightning bolt of nervous energy that never sat still. Even feeding it was difficult because it would try to dart out of the cage when the door was open. We never trusted it.
I just hope it wasn't like one of those canaries they used in mines to alert for high gas levels. If so, I fear we may be in trouble.
We aren't even thinking about replacing it with another. All my little girl talks about anymore is getting a cat and I absolutely wish we could, but I have allergies that would make it miserable to have one. That being said, the way she giggles as she watches those cat videos online, I'd be willing to live with the sneezing just to see her happy. Though, there is the aspect of the litter box which is pretty gross.
Right now, she is content with the artificial Baby Butterscotch horse she received at Christmas. It doesn't ever poop and costs nothing to feed. The only problem that arises is when her big brother wants to torment her by messing with it.
To anyone thinking of buying a dwarf hamster: I wish you better luck than what we had. They are cute to look at. At the pet store, that is.