Pioneer54: It's very much too early to think that anything has settled down (unless few new players join!) but you're right in thinking that the stairs will stratify. That's the whole point of them! ;-) ("Cliques" isn't quite the right word because there's no collusion or relationship between the players, their positioning is the result of their playing strength.)

Strong new blood will cause a minor stir as that player rises through the ranks but for the players in the regions below their destined destination it will only be a passing excitement. Weaker new blood will reach its level sooner.

I imagine that the Stairs will grow as a kind of pyramid. The players at the top can only go up when there are challengers below and they may be in short supply (either absent because the higher player has climbed too high, or too busy with each other and those below). This limits the absolute growth rate of the Stairs. For each succeeding lower level there will be a wider and wider choice of players. I suspect that those on the uppermost levels will be able to make a complaint about stagnation but I doubt that many players below would.