ISS cannot survive without humans to operate the systems. It would lose orientation, move in random directions, overheat, destroy itself. Once abandoned it will come down and we want to dictate where that occurs.
ISS will reach its service lifetime around early 2030's. Heat, cold, micrometeorites and radiation will have rendered it too expensive to repair.
Moving it to GEO from LEO would require another 6,000 m/s delta V. Each current boost accounts for about half a meter per second. Twelve thousand such boosts would be required.
There is zero science that could be obtained by boosting it to GEO and leaving it there.
Bottom line: No one is interested in saving it.