Indeed; a good library is a long-tail institution. The Harvard Library system has a large collection of books at the various on-campus libraries, but an immense catalog of infrequently accessed books at a "depository" warehouse off-site. Scholars can request items from the Depository and receive them within a day.

This split-storage model may a sensible solution for other universities going forward: prime and expensive library buildings on-campus can be reserved for quiet study areas and a few commonly-used books, with the main collection of books retrievable from a nearby location where land is less expensive. It also has the advantage of allowing books to be stored in the ideal climate for their preservation.

Fun fact about the Harvard Depository: books are organized not by topic, publication date, or anything resembling the Dewey decimal system, but rather by a metric that makes sense for high-density: physical size. Books are stored in barcoded boxes by height. Here is an artsy documentary, "Cold Storage," about the Depository:

https://vimeo.com/116603551

or in interactive form:

http://librarybeyondthebook.org/cold_storage/