How about simply trying to instill in the playerbase the idea,
"I will favor the newer, more active player unless an older player actively does a better job of convincing me and the realm they should have it"
The issue isn't one that can be enforced with rules or game mechanics. It needs a change in the way players think. "Trusting older players they've known a long time" has gone way, way, way overboard, to the point where new players just say "!@#$ it" and quit after a few months.
