Cablevision Breaking up is hard to do

If breaking up is hard to do, then why is everyone doing it? Cablevision Systems, the US cable group, is the latest media group to join the break-up bandwagon already crowded by illustrious rivals like John Malone’s Liberty Media and Sumner Redstone’s Viacom. The short answer is that the barons that own these companies are frustrated at the way the stock market has valued the collections of disparate media assets they have amassed. But will breaking them up make any difference? So far, there’s n...