Thought this was a great talk regarding the absurdity of companies buying back stock instead of reinvesting in research and development. The part where he talks about Boeing is very good, that starts about 53min.
It really boils down to three words: Incentives and Self-Interest Incentives relating to remuneration of senior executives, via preferred stock and/or stock options. Some of their contracts also stipulate hefty bonuses for executives relating to stock performance. These incentives encourage a focus on 'gaming' short-term stock performance at the cost of future value-creating prospects.