The thing about monopolies is that they are mostly harmful when they are truly monopolies - that is, there is no real competition for the product/service they provide and the price of entry is steep for potential competitors. But what constitutes the competition is not always obvious. Take Greyhound. Greyhound could be considered a monopoly in some areas of the country, but only when competition is defined as other companies of the same kind, i.e., other bus companies. We know that’s absurd. Greyhound’s competitors are also other forms of transportation: cars, planes, trains. Seen that way, Greyhound is just a teeny company struggling to survive in a jungle full of giants. Likewise, with political communication: the competition for political ads isn't just political ads of the unlike-minded; it's a much broader spectrum of the communicative diet we all feed on: newspapers, movies, TVs, novels, and of course the whole internet. Insofar as one is exposed to a diversity of viewpoints, one is less susceptible to being manipulated to agree with any particular viewpoint. A few alternative sources of information and opinion greatly diminish the influence of Powerful Others, whether they be moneyed interests or scientists in lab coats.

Speaking of which, remember the infamous Milgram experiments? This was where subjects were manipulated to “torture” (in their own minds) people with electrical shocks when scientists in white lab coats bid them to do so – even though much of the time, the subjects expressed qualms and seemed pained by what they were doing. Those experiments produced a “truth” that has passed into the cultural meme-basket: it doesn’t take much to make people do awful stuff. The trappings of authority are enough to command obedience.

My take-home message from the Milgram study is totally different, based on a less well-known variation of the experiment: sometimes another “subject” (actually in cahoots with the researchers) would be witnessed by the real subject. If that phony subject disobeyed requests to administer electric shocks past a certain intensity, chances were the real subject would also refuse. In fact, witnessing just one other "subject" who is seen to disobey the white-coated researcher reduced the level of subject obedience to 10%.

The essential idea here is when there is only one product or viewpoint and there is no exposure to competing products or viewpoints, resistance crumbles.  Even a little competition can make a huge difference.