That's one hell of a detailed story. Don't believe it. https://en.wikipedia.org/wiki/Conjunction_fallacy

About nanotech: if we have nanofactories, nanoreplicators shouldn't be far. Beware the gray goo accident.

As for AI, it will probably go from "quite dumb" to "way smarter than we are" in a relatively short time. At that point, everything else will be moot, because the AI will do pretty much what it wants (what its programming tells it to do) and we won't be able to stop it. Let's hope (or ensure that) its "wishes" are the same as ours.

Usually, predictions avoid themselves ;-)

But it's an interesting work of fiction in any case.

It's easy to avoid this future, observation of past future predictions suggests we're not very good at it. Therefore this future is unlikely and simply by relying on our poor prediction skills we can avoid this future without doing anything.