Even though senior management is awesome, middle management is full of "lifers" and new things are not done as effectively as they should be.
Excellent talent doesn't stick around. Why? Because doing as you're told is more valuable to middle management than being excellent and "rocking the boat". As a result, the great people who get drawn in by the big name and awesome technical problems to solve usually leave after a few years.
Because of the above, mediocrity is tolerated and even preferred.
The company moves slowly. Wall Street expects consistent, stable results and this trickles back down. Change happens but it's slow.
