Currently, the only way to prevent a user from using the Get a Link functionality is to disable all file sharing by site members. Get a Link creates a link which can be forwarded to anyone inside the company, granting them access not intended by the original sender.
Although site members can do the same through file sharing, it is much less likely this would happen by accident, or at least without careful thought.
We would like to be able to user member file sharing, but disable Get a Link.