stop selling the item until the incorrect price is corrected
Not a lawyer but couldn't they just refuse to sell it to you? We all know it would be bullshit but couldn't a company say "Oh that minimum wage clerk made a mistake, but don't blame them, just an honest mistake."
Or is the law, if it's on the shelf, it must be honored?
Exactly. This is Sony declaring victory in the console wars. You could argue "But Nintendo", but Nintendo was never playing the same game as Sony & Microsoft. You want to play Nintendo games, you buy a Nintendo. You want to play Sony games, Sony says you have to buy a Sony PlayStation.
I'm not a fan, but it could work.