I'm worried, it's not like I don't care. For example, I'm worried that Google is such a huge ginormous target, that at some point their Gmail will be broken. At the same time, there are benefits to sharing data. There are benefits to me, in Google using the information it has on my, to make my life easier. In this case, I judge that Gemini using my data to train, is a low extra risk for me. Compared to all other risks I take, for doing things in public. Including writing this on public forums, as you do too.
In general, I find the ongoing public scare about sharing data, to be anti-thesis to the original spirit of the Net, that was all about sharing data. Originally, we were delighted to connect to perfect strangers on the other side of the world. That we would never have gotten to communicate with otherwise. I accept there might have been an element of self-selection there, that aided that view: people one'd communicate with, although maybe from a different culture, would be from similar niche sub-culture of people messing with computers and looking forward to communication, having a favourable view of that.
> the ongoing public scare about sharing data
I think this might be a bit of a social bubble thing - I think it isn't a forefront concern for the vast majority of people.
I think you are correct there - the majority of the public don't care. They just try to get about doing their daily business and act the best they can under circumstances. So we just click "Accept" to any popup banner make it go away, accept "All cookies" 100 times every day, use Google mail/map/photos/drive and that all involves giving away data, even if in words we say we don't want to give data. So yes obviously the public by necessity act in a rational way, doing cost-benefit analysis. While a cadre of privacy obsessives have made my life worse by lobbying and having their bad ideas codified in the UL laws. Wrote about my experience in the UK medical systems here https://news.ycombinator.com/item?id=45066321