That’s because they’ve been pushing the iPad as a sort of Mac Lite, but they can’t do that unless you can plug peripherals or a thumb drive into it. You can 100% plug a USB-C laptop dock into an iPad, and it’ll work. You can even use a mouse with it if you really want to.

But they wanted to keep Lightning around as long as possible, because they made a commission on every single lighting cable that was sold; Companies had to license the rights to use the connector, and had to pay Apple for every one they used. That’s why Lightning cables were always a few bucks more expensive than a comparable USB-C cable. That extra few bucks was going straight into Apple’s pocket. It was a huge source of passive income for the company, which they were reluctant to let go of.