This is an eBay tactic that's been around forever - some special toy at christmas? Any other hard to find and hard to get item? Lots of people reselling the toy and then selling the box separate on ebay.
Because people will not actually read the listing and put bids in.
Things intended to be discarded but somehow escaped the trash can become pretty valuable. I saw an empty box that once held 100 primed, empty Winchester shells sell for $17,000. Only one other was known to exist.
If I had vision, I would have bought that '70 Plymouth Cuda that sold locally as just another used car in 1975. But I was newlywed and didn't have the $2600 to spare.