The ease with which a total newcomer was able to steal share from Google is real-world evidence that there wasn't really a monopoly and that Google competitors (Bing, etc.) just sucked and didn't want to spend the money to be better.
Well, courts disagree with your assessment and so do I. Yes, AI is a threat to Google. How much a threat remains to be seen. From normies I know, most of them are just using Gemini or whatever is on Google front page. They are not starting most of their searches on OpenAI or other ones.
ChatGPT has for sure the "first mover" strength for normies (you can hear it mentioned in TV, radio and in the street, but also lot of people just talk about "AI". So, IMO there is still space to be used as "the AI" rather then specifically ChatGPT.
It might also just be always referred to "ChatGPT" when talking about another provider, just like people saying "Kleenex" when referring to tissues.
Courts also decided you couldn't bundle a web browser and then turned a blind eye when it's done on a different platform with draconian restrictions against even installing an alternate browser.
They didn't "turn[] a blind eye" as they weren't asked the question again. There was no legal precedent established by the Microsoft case that required all future operating systems to have a replaceable browser engine. Also, the factual situations were quite different: Microsoft had a de facto monopoly on PC OSes in the late 1990s, while Apple never had a monopoly on mobile devices.
I asked Grok and Gemini and they both said there have been reports that Google search has dropped below 90% for the first time, so it’s significant but it’s like a 1-2% drop.
They stole share from Google because search is becoming obsolete, not because a new search engine came to town. It's like saying 5G stole market share from AOL's dial-up business. Search still has a use, and Google still takes > 90% of all search, so it's still a monopoly, and I'll add that Google is trying to leverage that monopoly to expand Gemini.