It’s impossible to know how long such a change will take to diverge. I guess my weeks/months estimate is baseless, I’ll grant you that. But some changes will have faster effects than others.

For example, if you remove a very famous person or someone from royalty, it will change the news cycle, which millions of people read all over the place. Each person who reads or would have read the news about it would have their life slightly altered, so this one change causes millions of differences over a large area. With so many changes, it’s likely that one of them will turn out more significant.