Tommy Wiseau’s The Room is one of film’s great basket cases. Ostensibly a melodrama, it was in fact a showcase for the tin ear, emotional retardation, cinematic illiteracy and self-pitying misogyny of its enigmatic star – a talentless ghoul with a Transylvanian disposition and accent like Arnold Schwarzenegger with a brain injury. The movie, with its incongruous tone, lack of internal logic and off-key performances, became a talisman for ironic viewers, a whetstone for blunt intellects. Anyone can watch The Room and feel like a genius. Its growing legend birthed a memoir by co-star and line producer Greg Sestero, The Disaster Artist. It would only be a matter of time before someone acquired the movie rights.

Unfortunately, the story of Wiseau’s folly was optioned by James Franco, a man whose skill as an actor, writer and director is arguably on the same spectrum as Tommy’s. The Room’s such a bad movie, with such a strange backstory, that nothing less than a Martin Scorsese Wolf of Wall Street-force treatment would have done, or at the very least someone like Tim Burton in his pomp, who understood how to make a biopic of a talentless filmmaker (Ed Wood) that mythologised the subject in a way he might have enjoyed while having fun with the director’s legacy; a cinematic treatment of a schlock pedlar, told with affection and a judicious drop of wish fulfilment.

Franco lacks either the filmmaking nous or storytelling chops to pull off a similar trick, and worse The Disaster Artist suggests he didn’t try. The film’s right to focus on the relationship between Wiseau and Sestero, and enjoys itself recreating moments from what must have been one of the most curious film shoots of all time. But what’s curious here is how pedestrian it all feels, how network TV.

The funniest thing you could do with The Room is turn it into a biopic of great depth and cinematic quality; a bad movie Boogie Nights, in which the low-rent backdrop makes for an excoriating look at the independent Los Angeles movie scene and the poor souls vying to get noticed. But instead the funniest celluloid catastrophe ever made becomes a mildly amusing celebrity piss take with a few moments of shoe-horned conflict and plastic pathos.

James Franco’s collaborations frequently look and feel like glib excursions for him and his pals – Seth Rogen, Franco the younger, et al, and The Disaster Artist plays no differently; the gang now extended to include Wiseau himself. This may explain why his tyrannical and sexually exploitative behaviour is alluded to but largely glossed over. The result is a movie the Room star can generally feel good about, enjoying the flattery of Franco’s good natured, albeit superficial comic treatment. But it’s a film that’s demonstrably useless at giving us the inside story or, if that’s an impossibility, an equally potent counter-myth. All in all, a waste of a wonderful opportunity.