"When you look at stock price movements the decline in prices is nearly always faster that the previous increase by at least a factor of two and usually greater."
Do you have the source for this? It sounds like an interesting read. I can see where that might be the case for bubbles, but I didn't know such a thing was so prevalent.
As to your last point, I would argue that the sheer volume of existing historical data probably encompasses more possible trends than one can invent. Especially if you think prices are psychologically driven, then you'd expect the trends to repeat themselves over and over again, no?