I'm sure Apple has done analysis... to see how many USB-C chargers they'll be able to sell. And has likely provided training to staff accordingly to get accessories sales up. Where the customer may have been happy with the 5W charger and crappy earphones included in the box, it'll be a MUCH easier upsell to a fast charger and good earphones now.
I think the point is that the charger itself is the waste being avoided. Not the charger packaging.
Surely Apple have done some analysis into what portion of their customers will not require an additional charger with each phone purchase.