Slowly, gradually, they will start doing that. The trade off for them is too much. Previously they claimed they don't read your personal emails like Google does. They soon realized they were losing big customer base because of people preferring Google Now over the pretty useless Siri. Now they have announced Siri Proactive, but for offering those features it has to read your personal emails. Now they claim they do read emails, but everything will stay on their phone. On the whole, users want intelligent features, and if Apple doesn't give it to them, they're going to go away.