The current retreat on analysts expectations looks a lot like 2001 line we observe from the chart in the ZH post
although it could get even uglier like 2008. Analysts will always be optimistic, because that is what sells stocks and pays their salaries. It is tough to get earnings right. First, you have to model the company and the sector, then make assumptions about the economic environment in which the company operates. Always take the reports with a grain of salt, but when they start revising estimates upward or downward en masse then pay attention.