Tom Cruise’s Knight & Day has now been in cinemas for exactly two weeks, in which time it has managed to make a total of $44 million at the global box office.

Since the film’s production budget was $117 million, and tens of millions more were spent on marketing it, this is not exactly an unqualified success for its studio, Fox.

Neither, though, is the (actually perfectly entertaining) flick’s disastrous performance being cheered at Paramount.

The studio which owns Mission Impossible and is due to make a decision in the next month or two about whether to green-light a hugely-expensive fourth film in the long-running action movie franchise.

They’re unlikely to cancel the project, which has been in development for years, and has already been scripted. But informed speculation has it that the film’s overall budget may end up being substantially reduced.

For Cruise, this will be hard to take. For decades, he’s been one Hollywood’s great bankers: a reliable actor who worked his backside off to promote films that would always live up to, and quite often exceed, their commercial expectations. Now he appears to be losing his mojo. Endless ink is duly being spilled in an attempt to explain why.  Some blame age (he’ll be 48 on Saturday), others his links to Scientology. Plenty have wondered if his public eccentricities are incompatible with being an all-American action hero.

But a wider trend is perhaps to blame. As I noted in our news pages last week, the so-called Summer Blockbuster appears to be in terminal decline. Audiences are tired of unimaginative re-makes and samey action flicks. These days, that rules out almost every film Cruise makes. If he wants to stay at the top of the tree into his sixth decade, he needs to reinvent himself.