The little known history of the Fairness Doctrine, and how it changed America

[True Federalist (진정한 연방 주의자)]

None of this explains why there aren't left-wing talk radio stations.

To figure out why left-wing talk doesn't work well on commericial radio, you need to consider the close to 800 NPR affiliates out there.  Granted, not all of them carry the various public radio talk shows.  Granted,  NPR is not as extreme as most commercial talk radio, as it is generally center-left as opoosed to the far right one associates with commercial talk radio.  However, the existence of NPR seriously degrades the commercial viability of left-wing talk because a large portion of the potential audience is already listening elsewhere.  NPR doesn't explain by itself the preminence of the right in commercial talk radio, but it does help to explain it in part.