Yes, any active member can be expected to be an editor. 4000 is not a strict requirement - those with good writing/editing skill can become that even before. Also, those who are good at pinpointing errors.
But going up the hierarchy is difficult. There have been no new moderator here for almost a year. Because those who are taking GATE are not made moderators. After GATE those who contribute back like Pragy, Arindam etc. are made moderators. Also, any mentors who want to help GATE aspirants.