Why do people optimize their old stuff if there is a great list of topics they can cover and write about?
There are actually several reasons for this.
We can name the first reason the “historical wave”. Trends come and go, get lost in history and appear to be in fashion every day, if not hour. There is nothing to be surprised about if topics you wrote about several months/years ago seem to be trending right now. Different times call for different trends, but it’s always vitally important to have an edge on them in any possible way.