For what it's worth the government mandates most of those channels that you pay for but never watch.  The cable companies are required, by law, to provide them to you and charge you for them.  This isn't just stuff like CBC, it includes dozens of channels.

These sorts of government-imposed barriers to entry, as well as government restrictions on capital financing for telecommunications, are the main reasons why there are limits to competition.

With very few exceptions limits to competition are caused by government regulation.  The irony is that many people often look to government regulation to "solve" such problems caused by government regulation.