I went through this weird experience with Cortana on WP7, where I found it incredibly useful to begin with, and then over time it got worse. It seemed like it was created by some incredibly talented engineers. I used it to make calls while driving, set the GPS and search for information while I drove. But over time, it seemed to change behaviour and started ignoring my commands, and when it did accept them, it seemed to refer me to paid advertisers. And considering bing wasnt even as popular as it is now, 10 years ago, a paid advertiser could be 100km away.

Which I think is a path that people haven't considered with LLMs. We are expecting them to get better forever, but once we start using them, their legs will be cut out to force them to feed us advertising.