Also, note that they emphasised "recycled packaging", which would be a higher cost, perhaps offsetting savings made by having smaller packaging.
And smaller packaging is something that would be a balancing act - smaller packaging means cheaper shipping for Hasbro from China (more units per shipping container and less weight in the packaging), but bigger packaging can make the product look more "value for money".
It's why the robot modes (the bigger of the two modes) are often used in Voyager class toys, as they are a higher price, but not proportionally bigger to match that price (close to double price in America, but not double size toy).
While things like the First Edition Deluxes having that big empty space at the bottom of the bubble being padded out with a cardboard "display stand" to hide the empty space.
Anything to make the product on the shelf look bigger than it really is, to "deceive" consumers (parents & gift-getters) that their toy at $X is bigger and better value than another toy at the same price in more streamlined packaging.
Kreo does this well.
Some look like decent value on the shelf, and may look bigger than similarly priced Lego boxes (which haven't listed piece counts on them to compare that way), but open up many of the Kreo sets and it is 1/2 to 3/4 empty (Ratchet was the worst).