In Hollywood, originality has become a bit like LSD: fondly reminisced about by old-timers (at least, the ones that survived), forgotten – and perhaps a ­little feared – by the new generation. This has naturally resulted in suffocating film-release schedules with franchises, but there's more cause for concern when this lack of intrepid spirit strikes at the very heart, and stains the tone and fabric of everything film-makers touch.

I've had a new feeling in the last few years, when I sit down in front of a certain breed of film. I call it karaoke cinema. It's a sense that what I'm watching has no independent reality of its own. The director is simply mimicking and mugging the style of another director, genre, or cultural touchstone, designated such a high-preservation priority that to introduce any trace of outside personality would be like putting a basketball hoop on a Chinese pagoda. It's not a case of whether it's an adaptation or remake per se; it's the absence of any intuitive manoeuvres that gives the game away. Without the other hallowed artefact, the karaoke film simply couldn't exist.

Watchmen had this effect on me. In following Alan Moore's panels with such glassy-eyed fervour, it didn't notice that staccato comic-book dialogue, seven times out of 10, can't work in a naturalistic medium. It was like an audio-book reading of the original, with a few million dollars' worth of special effects on top; a plane-crash safety video when I wanted the full plane crash.

Admittedly, some people do karaoke with more flair than others. But the bigger the performance, the more there is scope for embarrassment. The incorrigible ham in the house (and you have to weep when you think he was once Hollywood's bright hope) is Quentin Tarantino. He has always insisted on sidling into the frame to varying degrees of cringe, joining in the fun on his own and other people's projects, but the karaoke ethic has overtaken his writing, and directing, too, in the six-year lay-off between Jackie Brown and Kill Bill.

I found his two-part kung fu epic depressingly intent on strutting its stylistic stuff – mostly Shaw brothers chop-socky and spaghetti westerns – in a way which often made little sense and drained the farrago of all spontaneity. Fun to be doing at the time, like most tequila-soused stints down at Lucky Voice, but not something that necessarily deserves eternal playback on DVD.

Sure, Reservoir Dogs and Pulp Fiction fed off past cinema, but they chopped them up, stylised and synthesised them into something vivid and gut-wrenching; Kill Bill's distended story suggested that Tarantino badly missed someone up on stage with him, sharing creative duties; stopping him hogging the mic. Like his Pulp Fiction co-writer, Roger Avary.

Sharon Waxman's excellent book Rebels On the Backlot has a fascinating account of how Tarantino alienated Avary in his bid to live up to the myth of the great auteur, working in splendid isolation. But the self-regarding "the Nth Film by Quentin Tarantino" tag he insists on hanging on his projects, as if legendary status has always been his, looks like tragic over-sell these days. Death Proof showed more signs of life – the bar-stool, talky first half was quite brave – but it drove 100mph up a cul-de-sac.

Somewhere along the line, the weight of expectations – and maybe of pop culture, too – broke Tarantino. How did it happen that the 90s' most promising, edgy director came to be cinema's equivalent of the jukebox musical? This might risk a shuriken to the head, but Kill Bill's cousins are We Will Rock You and Mamma Mia! – nostalgia-fermentation machines that spew out doses of feelgood entertainment, high in pop-cultural E-numbers. I don't think the 29-year-old iconoclast who directed Reservoir Dogs would ever have wanted that said about him.

Sure, there is a lot about our culture that is backwards-looking, and plenty of lesser directors have done the same thing. You could even detect a hint of karaoke about Michael Sheen's on-going project in proxy-performance. This isn't doubting his quality, just that there's something safe about asking a very gifted actor to play a known entity again, rather than a blazing fictional cipher to light up our times like a flare from the dark. Pop culture is such a big part of our lives now – but at least someone like Tarantino used to have the ability to improvise to the inescapable backing track. And not even just ironically – there was something wistful, say, about Samuel L Jackson's final volte-face when he spoke of his "cold-blooded shit to say a motherfucker" in Pulp Fiction.

Interestingly, there are signs of new life. His summer 2009 project, Inglourious Basterds – if the script circulating on the internet is genuine, and it looks it – contains plenty of rambling writing and fawning cine-geek homage. But for something that's supposed to be a love letter to bristling, second world war men-on-a-mission capers, it's weirdly passive – and a terrible star vehicle for Brad Pitt, who hardly sees any action.

It gets caught up in a long plotline involving a film screening, almost as if Tarantino is turning in on his own obsessions. It feels self-referential, throughout, picking at the performance urge. There are allusions to French New Wave, and one of the best scenes revolves around role-playing, and that game where you have to guess the name of the famous person stuck on your head. There's a lot of final-act death, almost as if the director is clearing the boards. Near the end, Pitt's character comments: "I'm a slave to appearances." It's been a long time since Tarantino has written anything so candid.