Coming at it from the other angle, you want them to include the bits that a brand new iPhone user would need, with every iPhone. So they’re helpful for the new users, and a waste for many of the existing users – and a lot of the people buying iPhones are current iPhone users.well you might not be able to use your existing plug if it doesn't have a USC-C connector on it.
the iphone currently ships with a lightning to USB-C port, and the vast majority of charging plugs out there will have a USB-A connector.
so you either need to by a lightning to USB-A cable, or a power plug with a USB-C connector.
and Apple know this, so they are then able to milk more money out of the new iphone owner.
I’d rather see them ship just the iPhone and maybe a cable in the box, and have all the rest of the accessories be offered à la carte when you check out – the iPhone equivalent of “do you want fries with that?” Then everyone can get what they actually need, and nobody goes home with a bunch of extra bits that’ll just get tossed in a drawer.