[pc86]

Because Blockbuster Video played a pivotal role in early-1900s segregation in the United States?

I think it's much more likely it's just a reference to extremely popular and economically successful movies but happy to be proven wrong.

[saalweachter]

The movie term derives from a different piece of slang, a WWII term for a large bomb that could destroy an entire block.

Before movies bombing was a bad thing, a successful movie was "exploding" like a blockbuster bomb.

[MathMonkeyMan]

Yeah I heard it describes a movie where the line to get into the theater went around the block.

edit: ah, but wiki disagrees <https://en.wikipedia.org/wiki/Blockbuster_(entertainment)>