One would have to surmise that the oversupply was the catalyst. Without that first, none of the other stuff happens. But the history of the biz is littered with boom/bust ever since. Spindletop, East Texas, Middle East, and on and on.
One commentator yesterday suggested that market speculation acted to drive the prices far and fast, perhaps lower than the fundamentals warrant.
Such is the nature of markets.
Memories Of Houston, The Last Oil Plunge, And $10 Crude
http://www.freerepublic.com/focus/f-news/3244287/posts