I don't think there's necessarily a conflict between responsive design and mobile apps - I think there's actually a more interesting discussion around responsive design and mobile UI toolkits like jQuery Mobile, Sensa Touch, and Toura Mobile.

You can certainly have a responsive Drupal site within a mobile app that you wrap in PhoneGap, or in a web browser control inside a native app.

There isn't really a one-size fits all solution to any mobile scenario, because everybody has different problems, audiences, and budgets - what Drupal gives you is several different ways to build a mobile strategy with a CMS backend.

Offline access might be essential for some apps, others might need access to the camera for uploading videos. Or you might just want to sell your app through the App Store or Android Market.