I think if the license is revocable, then you never really own even a copy.

I only fully trust licenses that use wording like: "All rights granted under this License are granted for the term of copyright on the Program, and are irrevocable provided the stated conditions are met. " (from GPLv3) “Grant of Copyright License. Subject to the terms and conditions of this License, each Contributor hereby grants to You a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare Derivative Works of, publicly display, publicly perform, sublicense, and distribute the Work and such Derivative Works in Source or Object form.” (from ApacheV2)