The main reason is that it would be prohibitively expensive. The article covers this at a high level but doesn't go into details. The reason you pay $80 for a bundle is because channels like ESPN, HBO etc are expensive. Other channels like CMT, DIY etc are cheap. Bundles lets cable companies hide these costs and pass along the costs to the user. Would you pay $40/month to just add ESPN. probably not, you'd rather get $60 and get 120 channels.