Back in The Day, Nicholas Negroponte proposed the "Negroponte Switch", which was a prediction that everything wired would become wireless and vice versa. Terrestrial broadcast becomes coax and fiber optic cable. Meanwhile twisted pair becomes GSM and cordless. And so on. It was good enough to become a meme, especially if one didn't think too hard about it.
With approximately the same rigor (i.e. none) I will now set out to do the same. I propose that things that are paid will become free and vice versa. So music and books and other media are turning from paid products to free marketing, while free-to-air video and radio become a subscription or on-demand product for a fee. If I explain any more the premise will fall apart, so I'll stop here. It is now A Law. Obey.
(Also: Negroponte anticipated the Long Tail in 1994!)
UPDATE: "Over the next five years, revenues from paid downloads will far exceed earnings from advertising placed on free programming, according to a new industry study."