"It seems that the offer of a cheap burger, combined with what will inevitably become a collectible toy, has driven customers into a frenzy, with orders coming in faster than restaurants can serve them. “The most difficult aspect of this promo for the crew is the sheer volume of these meals that we are selling,” one worker told Kotaku via Reddit DMs. “Most stores I have seen have sold out of either the special boxes, Big Mac buns, or toys. Some places it’s more than one of these.”
I agree with what you are saying, but, boxes.
These boxes were designed specifically for the Adult Toy meal. It would have cost nothing extra to ensure the stackability of the said boxes. Regular Happy meal boxes are stackable, why mess with the stackanomics.
They haven’t had to design new packaging in years. I’m sure whoever created the original happy meal boxes is long retired by now.