I mean, Google harvests data from search engine queries. I doubt that LLM queries honestly leak all that much more information.
The issue is broader, just that people have gotten really comfortable for paying for service by selling access to their data, and I don't think that that's necessarily a great idea. Like, I'm not sure that everyone's fully considered all the ways in which their data might potentially be correlated with other data at scale.
Search engine companies are in the business of tying together users from session to another.