I know it's a popular thing to say, but switching to USB-C is not more environmentally friendly.
There are at a couple billion lightning cables and chargers already out there in use, not to mention whatever lightning accessories people have already purchased.
You are suggesting people throw those all out and buy USB-C which is ALREADY 10 YEARS OLD?
There's just no way that doing all that is going to be better for the environment - or do you know different?
Now, when the time comes for whatever standard comes next... then it may make sense for Apple to adopt whatever standard is created for interoperability, but for lightning/USB-C, that ship sailed a looooooooong time ago.