[1] https://en.wikipedia.org/wiki/Blockbusting
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.
Before movies bombing was a bad thing, a successful movie was "exploding" like a blockbuster bomb.
edit: ah, but wiki disagrees <https://en.wikipedia.org/wiki/Blockbuster_(entertainment)>
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.