The answer is friction. What % of this billion of users will bother to export their chat history (which is already a lot) and import another another llm. That number is too small to matter.
It’s not like Facebook where all my friends stay behind
That hasn't been true for a while though. Open a new chat tab in ChatGPT and ask it "What do you know about me" to see it in action.
How many of those care about their own particular history in the first place and what % of those at least actively manage it outside of standard chat interface or even hop providers? I think that % would surprise you.
The GPT-4o controversy is a good example. People got attached to 4o's emotional and enthusiastic response style. When GPT-5--which was much more terse and practical--rolled out, people got really upset because they were treating ChatGPT as a confident and friend, and were upset when it's personality changed.
In my experience, Gemini and Claude are much more helpful and terse than ChatGPT with less conversational padding. I can imagine that the people who value that conversational padding would have a similar reaction to Gemini or Claude as they did to GPT-5.
Yet non-technical users switched from Edge/Safari to Google Chrome.
Even if there is, browsers made it easy to import/export bookmarks and history.
You don't see Instagram willingly giving up all their data on users to Tiktok right?