These services do not lower mental transaction costs nor do they make it any easier for a user to value a penny's worth of anything - they simply make it possible for users to spend their money once they've decided to. Micropayment systems are simply payment systems, and the size and frequency of the average purchase will be set by the user's willingness to spend, not by special infrastructure or interfaces. There is no magic bullet - only payment systems that work within user expectations can succeed, and users will not tolerate many tiny payments. This still leaves the problems that micropayments were meant to solve. Likewise, the newspaper has a single cost, that, once paid, gives the user free access to all the stories.
Aggregation also smoothes out the differences in preferences.
Imagine a newspaper sold in three separate sections - news, business, and sports. If the newspaper charges a nickel a section, each man will buy all three sections, for 15 cents. If it prices each section at a dime, each man will opt out of one section, paying a total of 20 cents. If the newspaper aggregates all three sections together, however, Curly, Moe and Larry will all agree to pay 25 cents for the whole, even though they value the parts differently. Aggregation thus not only lowers the mental transaction costs associated with micropayments by bundling several purchase decisions together, it creates economic efficiencies unavailable in a world where each resource is priced separately.