I wanted to comment re. The future often resembles the past, and that may hold true here. Though it would be very nice if it were easier to talk to them about it. But I don't think their fears unfounded.
Labs here are very interested in campus access.
These researchers have full access with individual subscriptions. It's my distinct impression they hope to cancel - maybe not this year, but eventually. While getting the initial pricing scheme wrong in a way that loses the company money may not threaten Nature itself, I expect it could be career threatening for those who got it wrong. Librarians have such job security, I think we tend to underestimate what that must feel like. I hope libraries stick to the professional tone Harvard's letter has set and view Nature not as a problem, but as an ally which is having a problem.