The key issue I find with these bubble's is that, once the bubble forms - the media / hype behind the bubble causes the bubble to grow.

The growth of the bubble makes many people rich and therefore, creates even more mass media / hype about the 'bubble'.

This final stage makes everyone who is outside the bubble, wish they could get in on the 'action' of the bubble. People invest at any price, valuations continue to rise way past a realistic point and the whole thing is destined for failure.

When the first cracks emerge and the price proves to not support the reality of investment the whole things begins to tumble down.

I personally don't blame the people in the bubble initially for the collapse, but rather the media for driving the bubble's growth outside of the bubble's expertise.