You may be right, but I would push back on near total market capture. I guess it depends which market you're referring to, but even scoping to just software engineering I don't think they got anywhere near total capture. OpenAI has always had a good foothold there, Gemini, while it may be lagging at the moment, had some great results with earlier models that I'm sure have held some market, and that's not to mention the Chinese market.

I think it would be fairer to say that Anthropic held the mindshare in the Silicon Valley style tech scenes around the world and the companies built on that model, plus a substantial portion of other software engineering. Now it seems that's dwindling quite rapidly.