As you point out, the best way to make such decisions is for the faculty and library staff to make those decisions together. As we can do this and successfully meet budget targets, we will do so.
Faculty are obviously aware of the quality and relevance of each journal.
Librarians, on the other hand, fully understand the economics of scholarly publishing. It is our job, and we give these matters our complete attention. We know which publishers are contributing heavily to the economic spiral of inflation and which ones are working with us to try to contain costs. Obviously, for our collective long term benefit, we would prefer to support the latter and move away from the former. All of the members of the University community must become more effective consumers and we must leverage our fiscal resources to improve the scholarly communication process.