The thing that actually killed Blockbuster was Carl Icahn. He bought up a bunch of shares and wanted to quickly turn a profit on the company. At the time, they were investing heavily into a Netflix-like service, which required a significant up front capital investment and, therefore, was losing money. Icahn, wanting to make a profit, decided to cut spending and basically not look forward at all. He got a quick, massive bump in stock price and jumped ship as it was crashing into the iceberg. Blockbuster was caught in the middle of a paradigm shift and found itself massively under prepared to deal with it.