I’ll explain:

The status quo is that I have an iPhone with the included USB-A 5W charger. On the other end is a lightning connector.

Next iPhone comes out and Apple stops including the charging brick, but the included cable is now USB-C to lightning.

So I can’t keep the brick that I already own and actually use the new cable that Apple includes in the box. If I want to sell my phone with all accessories then I’m left with a cable and nothing to plug it into. If I want to keep using my old cable and brick I now have a spare USB-C to lighting cable that does nothing for me.

Basically Apple created a situation that doesn’t really make sense for any hypothetical user. Someone somewhere is buying a new brick or cable or has an extra wasted cable because of it.