Even apple still sells a lightning powered iPad so no, not all of them.

As a bob, if the next iPhone i get has USB C, it will be a different cable combattere to my iPad and airpods. Not much simplicity there😅

Introduced in late 2020 and produced at the very least till mid 2022. So if you’re buying one now it’s less than a year old. 5 years is a very long time for a battery

Actually it wouldn’t, batteries degrade even when not in use.