The fact that American libraries are actually conduits for funds from the government to the publisher is often ignored by American users, who seem to prefer to imagine that the libraries have independent sources of funds from their customers. Physics Archives in Particular From my perspective as a cognitive psychologist, physicists have an odd view of their literature. Some have told me, for example, that no paper over five years old is of any value whatsoever. In this view, the pre-print server is by far the most important leg of the triumvirate, the published papers are only for tenure, and the archives are useless. From my view, archives actually play an essential role in any science.
Science is after all a social activity.
The social nature of science is critical for establishing truth. Truth in Physics is established by the submission of ideas and results with their associated mathematical, logical, and experimental evidence to a public forum for evaluation. That public forum is made up of competent scientific peers who share a common understanding and are potentially capable of replicating the results and confirming the mathematics. Furthermore, if a new result can be shown to be in conflict with earlier established and confirmed results, then a resolution of the conflict is required before the new idea can be accepted as true. The archives play a critical role in this process of establishing truth.