Given that a major front in Walmart and Amazon’s battle is efficiency of warehousing, I wouldn’t be surprised if both have some fringe R&D funding dedicated to encapsulating pocket dimensions. Maybe they’re selling off an early prototype to raise more funds.
You could actually write a pretty fun piece of short Sci-Fi about pocket dimensions. It would start out seeming like just vanilla fiction about a group of friends at a con who meet a weirdo who insists their Tardis is real. They laugh it off as a joke, but then later one of them realizes surreptitiously that the interior is, say, 3 millimeters larger than the outside, like the 18 minutes of static in Contact.
