Very expensive films – they bomb (12)

I believe the answer is:

blockbusters

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'very expensive films' is the definition.
The definition and answer can be both man-made objects as well as being plural nouns.
Maybe there's a link between them I don't understand?

I can't explain the rest of the clue.

Can you help me to learn more?

(Other definitions for blockbusters that I've seen before include "screen epics" , "successful at the box office? - with 4d" , "Bombs" .)

I've seen this clue in The Everyman puzzle in The Observer.

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