I have about twelve Lightning cables (2 in car, 4 permanently installed at convenient locations, a few in my work bag, an couple in another bag and some currently missing) and one USB-C cable, which I use for charging my laptop.
At some point soon, perhaps when I get a new iPhone, I am going to have to start buying more USB-C cables.
I will then spend years looking at the end of cables to see what the connector looks like. Just like USB-A and B where I had to make sure they were the right way up, which takes at least three attempts.
At some point, my iPad and iPhone - and my family’s iPads and iPhones - will all be dead, and replaced with USB-C versions.
We are quite good at hanging onto devices until they can no longer have new safe batteries (installed by Apple) or have no real use, so this could be around ten to fifteen years.
This drive by the EU seems to mainly talk about power adapters, and how it’s a waste to have separate ones, but all the power adapters I use for phone and iPad have USB-A sockets.
With USB-C on both ends of cables, I expect I’ll have to buy some new power adapters soon. I will then have to have two adapters everywhere (one for my USB-A to Lightning cables), or buy lots of USB-C to Lightning cables for the transition period. To go with the USB-C cables for post transition period.
I’m not at all inconvenienced by Lightning and not at all desperate to have USB-C, and USB-C will be replaced by USB-D in a few years, probably many years before the Lightning devices have given up, to USB-C, so I will probably carry several Lightning to USB-A, several Lightning to USB-C, several Lightning to USB-D, several USB-C to USB-C, several USB-C to USB-D and several USB-D to USB-D.
* not counting the Switch. I’m not gambling with that - it gets its original PSU only.