the users who remain silent are not too lazy to ask for something more, they just don't want anything
Or maybe they just give up without trying as they do not expect you to do much for a minority of the users. It's also possible that they give up and leave, becoming non-users.
No they do not become non-users. They are still coming. Hell, the site traffic has never been so high recently although more than 88% are returning visitors. They are just satisfied with what they signed up for at the beginning I think.
How do you know if the people coming this week are the same people who came last week? Just because overall site traffic is increasing doesn't mean you have a low churn rate.
Or maybe they just give up without trying as they do not expect you to do much for a minority of the users. It's also possible that they give up and leave, becoming non-users.