I re-read your post. I agree that Apple should provide, at this point in time as they are transitioning their products to use USB-C ports, at least multiple charging cables with their newest iPhones.
Most of us still have USB-A power adapters. Currently, they appear to "push" consumers to get their USB-C adapters. Makes sense in the long run, but since they also decided to stop providing adapters with their phones, adding a second cable should not be monumental expense to them. Well, that would be my "2 cents."
My suggestion would be to let Apple know directly here: Product Feedback - Apple