Yeah but there has to be some reason they were so opposed to this.

Because Lightning came out years before USB-C was ready and is already an established de facto standard. There are well over a billion devices in use right now with Lightning ports on them, and billions of Lightning cables. You're balancing the advantages of switching to a "standard" against the reality that their customers already have Lightning stuff. I went several years with my Switch as literally the only thing I owned that used USB-C. Even now it's still common for gadgets to ship with micro-USB. USB-C has taken a long time to reach real ubiquity.

Lightning is also physically smaller and easier to plug in than USB-C.

Anyway, the point is that USB-C was not (and is not) this significantly, obviously superior experience for Apple's existing customers. There are real, tangible downsides that make it more expensive and more environmentally wasteful for at least hundreds of millions of iPhone users who will be upgrading.