It’s pretty simple. Rush grew up, grew rich, and grew famous on hard-hitting conservative commentary on the news of the day, especially the political news. That doesn’t mean he can’t talk about computers or golf or whatever else as well, but that’s (ostensibly) what his audience is primarily there for. If he wants to do three hours on Steve Jobs and blow off breaking political news, there are local shows on the weekend where he can do that.
His show on Steve Jobs and Apple products was boring.