That would be the kids fault for not specifying what he actually wants. It's the same with any other fad present. A brand of skateboard, a type of bicycle, a set of MtG cards, a specific computer accessory, sunglasses, shirts, skirts, shoes, the list of things goes on forever..
Because the company is not responsible for making sure their brands are not diluted?
There is no number on the cover of the books remember, so there is the company to blame for that, not the kid.
He specified he wanted the D&D PHB. He got that. He doesn't know from 4th or 3rd edition except upon inspection of the book and trying to use it.
The customer shouldn't need to specify things so finitely in some convoluted manner.
One wants a '72 Ford Mustang that is simple. One wants 4th edition D&D PHB, not so simple. the container doesn't indicate properly its contents.
Take the Red Box, made to look exactly like the old one. It isn't the customers fault for this, but the companies.
Again why AD&D changed the name, AND added numbers on the outside of the books.