I use Gemini at work, and ChatGPT for everything else 'personal'. Also from my non-tech friends, I usually hear them talk about ChatGPT and not Gemini or other models. I think, even if Gemini outperforms ChatGPT, there's definitely a strong 'first mover advantage' at play. I suspect that being outperformed by Gemini etc won't diminish their market share significantly.

It seems that at least in software engineering, Claude is popular and people are shoveling tons of money into it, whereas non-tech people are not inclined to pay for ChatGPT. Market share might not be so important if your competitor is raking in all the cash.