A quote from A. J. Liebling, a writer for the The New Yorker.
Freedom of the press is considered to be one of the cornerstones of a functioning democracy. Without it, you wouldn't know what you were voting on, and the process of voting would be worthless.
Silvio Berlusconi is Italy's wealthiest person. He also controls more "freedom of the press" than any other person in Italy. Of course, he also happens to have been elected to the most powerful post in Italy multiple times. Not too surprising.
Control over the media translates to control over the ideas and issues discussed at election time. The more that control is concentrated into fewer hands, the less of a real democracy the nation becomes. Authoritarian regimes use the same method to win their sham elections. Since they control the media, they control all discussion and critiques of various policies. Once you control the ideas, you control what people will vote for. The more control of the media you have, the easier it is to control the vote.
While the electorate may not be "illiterate" in the sense that they can't read or engage in complex feats of engineering, they can still be rendered politically illiterate by surrounding them with media that only pretends to be "fair and balanced" or "pravda" when it is not.
As the gap between the rich and poor widens, it shouldn't be surprising that many members of the wealthy classes would use their growing power to influence the media. The more influence they gather, the more they can consolidate their wealth, and further widen the gap. If left unchecked, the democracy itself would be destroyed.
As Abraham Lincoln wrote in 1864:
"I see in the near future a crisis approaching that unnerves me and cause me to tremble for the safety of my country; corporations have been enthroned, an era of corruption in High Places will follow, and the Money Power of the country will endeavor to prolong its reign by working upon the prejudices of the People, until the wealth is aggregated in a few hands, and the Republic destroyed."