There is some truth in it, they reduced the iPhone Box size, so they can ship more iPhones in the same amount of space thus reducing emissions for transport. What they should have done tho is allow people that buy a new iPhone or iPad to get a charger for free if they want them. That would still reduce emissions from transport… but they choose the way that people would need to buy a charger and with that also sneakily increasing the iPhone price by removing things that were included with earlier iPhones. (charger $19 + EarPods $19 that are no longer included with modern iPhones).