When an infant can go through 100+ diapers over the course of stay, thats either a checked bag fee, or have Amazon ship it down for free, for the same or less than it would cost just to buy the diapers at Baby R Us or similar. Or just compare the prices that Garden Grocer will charge for baby food or anything non perishable with what Amazon Pantry would charge to ship down for a small fee (or free if you get a Prime credit). WDW did it to themselves by increasing prices for food goods on property, and using DME to convince people to not get a rental. If people can save a few bucks by shipping things down, they will.
I do wonder why they have exclusions for Amazon Prime Now, but not Amazon Prime or regular Amazon.