Secondary causes versus primary cause

Different cycle may have different causes. Although I expressed that late 70s and 80s' causes were different from this cycle's causes for slump, these so called "causes" may not be real causes. The real cause may be the relative buying power over housing price ratio. When it got too much out of whack, it must reverse. The so called "causes" such as easy credit, inflated income, job losses and etc may best to be classified as secondary causes that work together to adjust the primary cause, in pediatrician's word "affordability", in my word "relative buying power over price ratio". It's the same thing any way.