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.
This is interesting, but doesn't have to be correct.
If Blockbuster had kept pouring money into the new service, maybe it would have lost it all - I see no reason to think Blockbuster's movie rental franchise business would have 'transferrable skills' to allow it to succeed at streaming.
If it had been trying to pivot into a pizza delivery business (perhaps more transferable, in terms of locating franchises etc) would Icahn still have been 'killing' it?
My point is, maybe it was already dead and Icahn just prevented it from wasting a lot of money on the way down the drain.