Monopolies are not inherently bad. A monopoly on some good or service might be that way because it provides the best product at a fair price and there's no way somebody else could beat them. It's only when a monopoly starts using its position of power to either unfairly gain advantage in a similar market, start screwing over customers that they become "bad," or some other tactic that ruins competition or hurts consumers.
Yes they are. They are bad because they are a massive risk center to their customers. For a small industry this is just kind of annoying, but for a massive one it can have a detrimental effect on the entire economy and not having massive single points of failure in your economy should be (and sometimes is) considered a matter of national security.
What about wireless spectrum? Should we just give access to spectrum to everyone who wants it? Your radio, cell phone and wireless Internet would stop working within weeks, I'm sure. Sometime monopoly is not only good, but necessary.
That the status quo for RF spectrum is that of government granted monopoly in most of the world is not evidence that this is a necessary way to operate. In fact there have been numerous proposals to change the regulation of important RF ranges into a more typical commons based usage model. e.g. the "whitespace" wireless broadband systems that are still fighting their way through the FCC regulatory quagmire in the US.
I'd even argue that the regional monopoly system we currently have actually frequently does have to act in communal ways in the best interests of different providers across regulatory regions. People without billions of dollars on the table just aren't allowed in those conversations.
I'm not entirely sure that we have locked out people without billions of dollars. I followed closely and commented on the low power FM rollout (I managed a college radio station at the time) and though it wasn't perfect, I do feel it was a major step. It allowed many small broadcasters to enter the market that would not otherwise have had an opportunity.
I don't have anything against whitespace spectrum (though I do feel it becomes a shoving match of who has the biggest tower), but there are certain applications that demand a monopolized spectrum, such as cell phones. If providers were not able to provide national, dedicated networks, the cell phone industry as we know it could not exist. This is not to say that cell phones wouldn't exist (perhaps just a patchwork of regional providers), but the level of seamless service that consumers have come to demand would not. Even a patchwork of regional carriers would require regionalized monopolies. Why would you go to the trouble and cost of building a tower if someone can just build another, larger one next to it?
Insurance for one. The original idea for insurance was that it was a not for profit enterprise that gets better the more people that are participating. We've bastardized that with private insurance, but in theory, an insurance monopoly is a good thing since it creates the best allocation of resources.
Utilities, roads, wireless spectrum, really anything that requires everyone to agree on a standard set of rules for it to work. Can you imagine if roads were built like web browsers? It's one thing to have a website not work in your web browser, but when someone's safety is at stake, I'm a big fan of standardization.
Of course -- and I've said this before -- anything important enough to be a monopoly is important enough to be heavily regulated in order to operate in the public interest (as utilities, roads and spectrum are).
Major League Baseball and the NFL are government sanctioned and enforced monopolies because breaking up the talent into competing leagues would be be ad for the sport.
Over the years, MLB has been exempted from antitrust enforcement.
The government does nothing to enforce monopolies in the sports world (remember the XFL? It failed because not enough people watched. Also, there are pro/semipro baseball teams not affiliated with MLB. A somewhat local to me example: http://en.wikipedia.org/wiki/Traverse_City_Beach_Bums).
