Mediums change, but what’s unique about Medium, and so many other digital platforms, is that that these changes often apply retroactively. You may “finish” a post on a platform, but to those who own the platform, it’s never quite finished.
I think of this as digital wear & tear. If you leave a book on a shelf, it gets dusty and the pages turn yellow. If you leave a post on a platform, the <div>’s change and the header gets redesigned.