By the time the libraries realize how badly they’re in hock to you, their faculty will depend on all your journals, and the libraries will have no choice but to cough up the money for your extortionate fees.
But you’re losing sleep when libraries complain about your journals’ prices. Relax. Librarians are whiners. All fuss and bother; no action.
What are they going to do? Cancel the journals you acquired? Imagine the hue and cry from the faculty who rely on them. Most librarians won’t contemplate such action, devoted as they are (poor, well-meaning saps) to the needs of faculty and students. You think they’ll band together with other libraries and mount a boycott? If they can’t bring themselves to disappoint faculty and students at their own institutions, how can they imagine disappointing those they serve at multiple institutions?
I suppose it is theoretically possible that the Association of Research Libraries or the Association of College and Research Libraries (yes, they are two different institutions, thus making my point about libraries’ inability to coordinate on this or any other movement) might someday make noise about a boycott. If so, just make some noise in return about the unfortunate possibility of a lawsuit alleging restraint of trade.