The reason you see the same lines from channel to channel is because these news outlets buy their stories. They are pre-written and arranged and often include video footage. They do this because original reporting is expensive and it's silly for a hundred reporters to cover the same unimportant subject when a single person can do it and sell it to others. Everyone wins, but it does result in many places not altering the script very much to make it more original. To suggest this is a government plot is silly. Again there is no evidence of this.
PS- Prove there is no evidence.
PPSS- A negative four vote count on an article pointing out that the media in the USA is mostly propaganda (on a site which bans people who disagree with the sites desired narrative) is... well, super ironic, and a form of a badge of pride.
I spent 6 years living abroad and got to see the perception of the USA (south america counts as "americans" too) -- in the media in foreign countries, including some discussions of politics with people in europe and south america.
I can answer your puzzle very simply: The media in the USA is controlled by the FCC to a high degree, and all we get to consume inside this country is propaganda of one sort or another. From Fox news to CNN to MSNBC to your local affiliate, you get a very slanted, very consistent take on the news.
John Stewart used to run clips of various reporters reporting on the same story and using the exact same words. This was supposed to be funny- but the thing is, this is because the government manufactures the news for us. Investigative journalism is basically a dead art. And the places that do it still (like Rolling Stones coverage of the housing bubble) are basically putting forth political propaganda pieces as if they were investigative journalism.