If found this quote on another forum:
My first ski teacher and then director of the ski school was an old polish team member. At that time the stem Christie was very much alive. He believed in final forms in skiing. That every part of the progression had to be mastered correctly to the letter. The snowplow turn had to be done perfectly before the stem Christie could be introduced and so on. I can remember teaching a parallel lesson and "Stan" would ski by toward the end of the lesson and give the class a quick stem Christie lesson.
I think the difference between how many European schools teach and the American schools teach is the focus of learning and mastering solid fundamentals in the European systems. The American culture wants to shortcut the fundamentals and move on to harder terrain without having the skills and technique to ski it in control or safely. That is one reason the direct parallel is so popular. If people want to ski parallel, then why teach them the wedge or wedge Christie? With the amount of groomed runs in many American ski areas, many skiers can progress to black runs quite quickly and get down them satisfactory. Put the same skier on a black un-groomed run, they quickly find out that they are an advanced beginner, with few fundamental skills, on terrain were they don't belong.
I was very thoroughly taught the stem christie. That led me to be a fearful skier in the blacks and even the steeper blues, sometimes struggling to initiate a turn even though I wasn't skiing very fast. The amount of effort it took to throw my body down the hill, or "DIVE!" as my ski instructor taught me, was tremendous considering the fact that I was stemming like crazy to control my speed. It was hard on my knees too.
So glad I found Harald's stuff and PMTS. Now I can ski way faster (or slower) in the steeps with my more control than when I was clinging for dear life with my stem. The knee pain is gone too.