In a group about media manipulation, this obituary is a good commentary.

The obituaries that have appeared in the mainstream corporate media have catalogued many of Limbaugh’s verbal outrages ... Lacking in such assessments, however, is an analysis of what Limbaugh’s career reveals about the nature of American capitalism and the trajectory of its political system. He was a thoroughly disgusting human being, a mouthpiece and apologist for reaction and defender of everything backward and benighted in American society. But his rise to wealth, fame and political influence came under definite historical conditions, and these deserve consideration.

Particularly noteworthy:

In 1987, towards the end of the Reagan administration, as part of a bipartisan campaign of deregulation, Congress repealed the “fairness doctrine,” which required broadcasters to provide equal time to those attacked by radio or television commentators. Limbaugh celebrated what he called “liberation” by moving to New York City and launching a right-wing talk radio program on WABC, flagship of the ABC radio network, which was soon syndicated nationally.

... The timing of Limbaugh’s rise is significant. It coincided with the collapse of the Soviet bloc, from 1989 to 1991, which touched off a wave of euphoria in the American ruling elite, whose main political precept had been virulent anti-communism ... also important for the American political stage was the utter collapse of the US labor movement, with the trade union bureaucracy’s betrayal and defeat of strike after strike, beginning with Reagan’s smashing of the 1981 air traffic controllers’ strike ... The resulting political disorientation and confusion within the working class, compounded by the suppression of the class struggle, facilitated the rise of a form of right-wing populism, of which Limbaugh was one of the foremost practitioners.

The whole article goes through his entire career—it's worth reading overall.