In my ideal world, data should go to the vendor by default. As you said, it helps the product improve by feeding it more data, and it's simpler for most users

In my ideal world, data should go to the vendor by default. As you said, it helps the product improve by feeding it more data, and it's simpler for most users. With that being said, privacy concious people should have the ability to opt out, and either not have their data stored permanently at all, or allow them to store it on a personal server. If you chose to do that, it's on you to make sure your server is setup in a way to ingest the data, so no additional work for the vendor. I suspect in reality most vendors would not provide that option, because data is so valuable, which is why it's important to have laws that allow us to protect it.