Have you ever had the occasion to talk to a Mormon from a congregation you used to live in? Or perhaps you've been the one who still lived there and you talk to an old ward member who had moved. Typically the one who moved will ask the one who stayed behind about changes in ward membership and leadership. "Who's the bishop now?" he'll ask. And I've found that, more frequently than you would think it should, the answer is, "Oh, it's someone who moved in after you left."
Maybe I'm wrong. I'm not keeping stats or anything. It just seems to me that bishops tend to be newer ward members a lot. Why is that?
I have two possible explanations. Maybe they're both accurate, or maybe neither is.
One: many are called but few are chosen. The process of becoming chosen involves being proved to see if you will do all things whatsoever the Lord God commands you. I think it is likely that, prior to a leadership calling coming, a trial comes first. And in the modern world, there's no more-common trial than unemployment and relocation. The soon-to-be bishop spends a period of time being humbled and relying on God, and responds to directions with a "thy will not mine" attitude, which results in him moving somewhere he wouldn't have chosen on his own. Once he's demonstrated this, the Lord uses him in a leadership position. Thus the moving into the ward was part of the trial that prepared him to serve as the ward's bishop.
Two: man looketh on outward appearances. Someone who has been a long-time ward member might think he has the ward "figured out." He knows who is leadership material and who isn't. But the Lord looketh on the heart, and the most-effective way of getting a bishop to take the Lord's direction is to use a guy who doesn't have any preconceived notions. If I had to pick a Relief Society president for my ward, I'd have a mental list of possible candidates. But if I had to pick one for your ward, I'd have to rely on direction from God, like I'm supposed to.
Anyway, the next time you ask about your old ward and find out that the entire bishopric is strangers, perhaps one of these two reasons is behind it.