I replied at the artima forum:
I think it's because companies are insular in nature, and the longer one is in the company, the more skewed their view of the real world is. Companies tend to stabilize things, (to have repeatable process, etc) so over time become a less challenging environment than the real world for the people who have been there a long time and have learned the politics of the company. These people tend to be managers and lifers (hoping company won't fail before they retire).
In this safer environment, the instinct is to hold steady. And that means not introducing new technology as rapidly as in the real world (which means you fall behind eventually) and not bringing new ideas as rapidly as in the real world (which means you fall behind eventually), and ultimately you have old technology and old thinking and that will not produce solutions to real world problems.
This is why startups are more brutal but more innovative. They live in the "current real world month" and have to deliver valuable solutions to actual current problems.
So, collective stupidity happens when people try to apply organizationally-reinforced old thinking and old tech to current problems.
I realize I didn't answer the question fully, but I think what needs to be done becomes painfully obvious.