Which actually proves they aren't much of ninja anymore. If they were awesome ninja, like the Third, they wouldn't have doubted they could find Tsunade. But since they are just old geezers now, they thought: "Nah, Tsunade never visit the village anymore, and thus to find her, we would need to leave the village... Oh noes! Leave the village! No way with this arthritis. Let's take the old pervert Jiraiya."