Not really sure which side of this fence I sit on. Most devices (even Apple’s own with MacBooks and iPad Pro) use USB-C now, so there would definitely be synergies by having iPhone use USB-C connectors instead of lightning.
However, I can also see the argument that it arguably could create more e-waste in the short term as people no longer have use of lightning cables for new iPhones. Although, to be honest, lightning cables don’t last forever, I seem to only get about 1-2 years before they stop working or get finicky and need to be replaced. Theoretically you could significantly reduce the number of charging cables required going forward if a common charger is used for all mobile electronic devices (users won’t have to buy as many extras for multiple locations such as house vs car or different rooms as they can share the cables that come with the various devices).
With all that said, I’m a bit hesitant for a standard to be enforced by a government authority, as I could see how that would stifle innovation. We might all still be stuck with USB-B if Apple hadn’t leap frogged with the lightning (frustrated with slow progress of standard development with USB-C). Ideally, companies should look to move to a unified connector, but not sure in the long run being forced to have a common one is a good idea.