What's the worst thing that could happen to Google?
iterationx: A superior Chinese language search engine coupled with a deep(er) recession in the US would hurt their profit machine.  The web could also change with regards to categorization. For example if I want a book I go to Amazon, if I want to learn about boardgames, I go to boardgamegeek, if I want general knowledge I go to wikipedia.  So on a long enough time line if I want to do X on the web, I go to Y.  Where Y is not Google.  Also I assume one of these days someone will figure out how to implement a metaverse that everyone wants to use and then searching might be different there as well.  Or maybe Wolfram will figure out something useful to do with his engine.