I think (armchair analysis) it's a combination of two things, one is that it's by choice - people enjoy using LLMs, they find it valuable and convenient. As for social media, companies and society itself successfully managed to gamify people sharing their personal lives on the internet, to voluntarily reduce their own privacy. Also because they still believe they have a choice in the matter, by e.g. not posting or sharing things.

The other thing is the boiling frog analogy, it wasn't a sudden "we're at war now so you get a camera in your house" moment (iirc 1984 skips over the transition to an authoritative state though), it's a slow, gradual progress. People got used to taking selfies, then applying a filter, then using facial scans for identification, then a cool app that puts your face on movie scenes and now the company behind faceapp and co has detailed facial scans of millions of people.

Europe tried to limit it via legislation, but that's a lot of after-the-fact policing and that's just Europe.