Commerce is about pricing, and pricing is about scarcity. Scarcity, of course, demands no easy substitutes.
Some news websites are foolishly putting up paywalls, requiring readers to pay by the day or the year to see what's there. This is foolish because substitutes are so easy to find. If I can't get to the Times of London or Time magazine, no problem, I'll find the same news (or almost the same news) somewhere else.
This is the mistake that book publishers are making on the Kindle. I was mildly interested in the new biography of Henry Luce. But it's $19 on the Kindle. That's outrageous in a world where there are plenty (more than I can ever read) of great biographies for less than $10 on this very same device. (In fact, I can buy the biography of his forgotten partner, the actual founder of Time, for $4 in paperback or $10 on the kindle.) Is a biography about someone else a perfect substitute? Not if you're writing your dissertation about Luce, no, it's not. But the publishers seek a broader audience than that, don't they?
The internet has dramatically widened the number of available substitutes. You don't have to like it, but it's true. That means you have to work far harder to create work that can't easily be replaced.