Listening again to Bob Brinker's Moneytalk, I wonder why the host-and-caller interaction on radio isn't always conducted as if the two were talking on walkie-talkies. Why allow both people to speak at once? It's irritating enough to have to try and distinguish which talking-head is saying what on TV, when you're able to see them. In the car, with the distractions of the road and only the audio to go on, it's infuriating.
It wouldn't be a difficult thing to execute. It's standard for show hosts, especially of political programs, to cut off callers before they've made the point the screener put them on to make if they are perceived to be out-of-line. The host needs to simply press the mute button whenever he says anything.
An interruption that forces the caller into silence is preferable to the cacophony that often follows when the host feels the need to challenge or correct the caller in mid-sentence. This gives the host precedence, but it is his show, and the vast majority of the listening audience wants to hear him blather, not the caller. It also increases the amount of time the caller will be allowed to remain on-air--if he shuts the caller up temporarily, he'll be less likely to kick him off for good as quickly. And it makes it more difficult for points made by either party to be ignored--think how much more difficult it is for the President to circumvent questions when he's calling on specific reporters to ask them than when they're all squawking at him (usually as he's ending the question-and-answer session).
More even than for political shows, this is desirable for advice-dispensing programs. Nothing is less necessary than the caller frequently saying "Ah," "Oh," "Uh-huh," "I see," "Okay," and similar tripe as his question is in the process of being answered by the host. It distracts the listener's attention away from the advice the host is giving, and I can only wonder how it steals the host's focus.
Then again, it seems the same answers to the same questions are given over and over again, especially on financial shows, so maybe the distracted listener is desirable--he'll have to listen for the same answer seventeen times before he actually digests it.