I really like this Beverly Goldberg piece. She makes an important point with the question: "why should it matter that a 'single eBook license to a library may never expire, never wear out, and never need replacement?' Most printed books last for years in library collections and that didn’t affect book sales when the economy was a bit more flush; those loanable titles just whetted the public’s appetite to borrow and buy more. Why should that pattern change for e-books? If anything, there may well be more incentive, since a borrowed e-book vanishes from a patron’s e-reader device when the loan period ends even if the borrower wants to retain the copy for a few more days to finish it."
See also this Slate piece, which also cites studies about the contribution of the secondary market to the primary market. As I wrote to a publisher friend, "I think the publisher/author fear of resale/lending is not only bad for society, it's bad for YOU."