People are forgetting that you usually have to return your accessories (charger brick and cable) when you trade-in an old iPhone. So it's not like people have that many chargers laying around.
> you usually have to return your accessories (charger brick and cable) when you trade-in an old iPhone
I've never ever done this and I've traded in every single iPhone I've ever owned. You just reset it, hand it over out of your pocket, and they don't even ask any questions.
I did their upgrade program trade-in for the past 2 years, not once did they ask to include the charger. The box instructions (in which you give them back your old phone) explicitly mention what needs to be included, and the charger (or any other accessories) is not there.
Technically you might not count it as a trade-in, but it is effectively the same procedure. And I had plenty of friends who did trade-in not that long ago, they weren't asked to return the charger either.