> I'm willing to bet that if you swapped out GPT with Claude, Gemini or Llama under the hood 95% of their users wouldn't even notice

You can say exactly the same about Google and Bing (or any other search engines), yet Google search is still dominant. Execution, market perception, brand recognition, momentum are also important factors, not to mention talent and funding.

Not everyone who wants to invest, can invest in this round. You may bet the investors are wrong, but they put money where their mouth is. Microsoft participate, even though they already invested $13b.