I'm not sure if anything has changed there. Huge bulky items have always been delivered from a warehouse ~days later. Online hasn't changed anything with that, I don't think. Sure, sometimes you'll get lucky with a popular model they keep a few of in-store, but that feels like the exception.
You can't go to a mattress store and walk out with a mattress either, generally.
But they do have these items in the store out on the floor, they could have done it but it just seemed like they didn't want to make an effort. I realize your choice of model is going to be limited if you are in a hurry, but if you want to compete with amazon, being eager to sell people appliances day of would be a good way.
You can't go to a mattress store and walk out with a mattress either, generally.