Stalemate lines are a bunch of crap! That is to say, stalemate lines occur when they are allowed to occur, and are very rarely forced to occur. Thus, in my opinion and from my own experience, both as a player and as a game-master, stalemate lines form mainly because of the philosophy of play. Strong players who tend to win are also the same ones who will not allow stalemate lines to come into being if they can help it.
Another way to look at it is that stalemate lines require, in general, at least thirteen or so units. Consequently, those players who form stalemate lines are those who give up too easily or early, or who could not force a win -- or, more importantly, were allowed to form a stalemate line. To me, owning 13 units with no one ahead of you generally means that you have an excellent chance of winning the game.
It is at this point, the middle game, when a power has grown to thirteen or so units, where important decisions are necessary in order to maintain the momentum of your own growth so that you can win. The beginning game's most important aspect is to establish an alliance and fights among your enemies allowing you to survive and to expand. After the initial expansions, the game comes to grips, in order that the major powers and their minor power allies must fight each other. In order to get past this middle game, you must maintain your momentum.
To maintain momentum, the best possible technique is to employ your weight around Europe in a combination of power and diplomacy. The good players win their games here! The almost good players are good tacticians and study stalemate lines -- but they play defensively and do not worry about the real game. For if they did, they would not have to worry about building a stalemate line for defense, since they would have maintained their own momentum of growth.
I am not against developing stalemate lines if your cause is otherwise hopelessly lost, but I believe that in most cases this would be, at best, a poor alternative to what you could have done to maintain your momentum. The balance of power on the board with respect to the good players is maintained in their own favor. There is thus far less likelihood of stalemates or draws forming in the game.
My game style is different from that of the player who would employ a stalemate line. I play to break lines to maintain and nurse allies who can help my cause, or as the case may be, our cause. Tactics do play a part, but only in the offensive sense. In brief, to study stalemate lines is a waste of time when you could study techniques of being able to decipher the balance of power and to make it lean in your direction. If this is done, you won't need any stalemate lines.