The branding is so strong and it works well enough (I’d say, according to the perception of most people) that it’s just the first “obvious” choice.

Akin to nobody getting fired for choosing AWS, nobody would think poorly of you using ChatGPT.

I don’t think Claude has that same presence yet.

Google has a reputation for being a risk to develop with, and I think they flopped on marketing for general users. It’s hard to compete with “ChatGPT” where there’s a perceived call to action right in the name; You don’t really know what Gemini is for until it’s explained.