Satire died, so we are told, the day Henry Kissinger won a Nobel Peace Prize. There were no more jokes to be told.
Similarly, the blood is now drying on the corpse of camp, and the man standing in the dock accused of its murder is Tom Cruise. After Rock of Ages, there is nowhere else for it to go.
Cruise has surely already tried everything he can possibly think of to win an Oscar. He's dived off buildings on various Missions, he's shown his soft side in Jerry Maguire, he's climbed into a wheelchair for Born on 4th July, he's even deconstructed his own alpha-male image for Magnolia.
Now, in Rock of Ages, he's taken one more massive leap, sticking a pin through every single one of his meaningful, hard-stared, jaw-clenched portrayals in a 30-year career. And he's opened his mouth and sung a catalogue of 80s rock power ballads to boot. It really is one massive, camp-as-Christmas six-string roll of the dice.
And the gods have smiled, with a role he possibly wouldn't have had the confidence to play pre-Tropic Thunder. The director Adam Shankman (Hairspray) thought it would be a wheeze to have the world's biggest film star play the world's biggest rock star, Stacee Jaxx, and so it proves. He is a butt-clenching, cod-pieced and tattooed, wounded warrior, puffed up like a butterball turkey and strutting like a man on the run. In some shots, he looks like the long-haired teenage hockey player he was once, in others, he looks as rough as sticks, but he gives it everything.
And takes everything. After his first highly-anticipated rendition of Bon Jovi's Dead or Alive - note-perfect, of course - would you expect anything less of Hollywood's last samurai? - he obviously didn't want to surrender the mike on what amounted to a massive-budget karaoke evening, so we got the more reflective I Want To Know What Love Is.
Malin Akerman plays a Rolling Stone journalist seduced against her better judgement into a steamy Stacee Jaxx encounter
By the time he motorbikes into the final set piece, it's hard to tell where Jaxx finishes and Cruise begins. Or perhaps Jaxx is Cruise's picture in the attic - the one he's had tucked away, saved up for the day he finally gives up trying to prove he's so much more than symmetrical beauty, and loses himself in something he understands viscerally - the weight of public clamour and expectation. And you know what always happens just when you finally give up trying...
In other news, "leads" Julianne Hough and Diego Bonata (Mexico's Justin Bieber, apparently) are cute enough as a lovestruck couple brought together, then apart in the nightclub of their dreams. As in something like Rocky Horror, they're not too charismatic to distract from the real stars of the show.
Russell Brand and Alec Baldwin must be one of the screen's unlikelier pairings, but their collective appeal means neither of them has to bother acting that much. Or should bother trying, in Brand's case. His accent is a game Brummie - as an homage to Ozzy Osbourne, he has revealed - but he literally forgets to keep it up for a whole sentence. At first I thought it must be deliberate - not so much collapsing the fourth wall as throwing an axe through it - but, on reflection, I'm not so sure.
Catherine Zeta Jones is on fantastic form, showing off the same singing, dancing roots that won her an Oscar first time round in Chicago. She's given less to do here, but never mind that - when did CZJ become one of those beautiful, ball-crushing, campy-vampy women like Sharon Stone? It's a long way from Darling Buds.
The singing is fine, a lot easier on the ear than the un-dulcet tones of Mamma Mia! Either engineers have got better at accommodating what the director calls, happily, "unrefined" voices - somewhere along the spectrum between untrained and unlistenable - or rock is lots more forgiving.
Tom Cruise had to learn to sing for the role of Stacee Jaxx
The story, simplified from the stage version, doesn't take too many twists or turns to bring us back where we belonged - happily boogying along to - guess what - Don't Stop Believing. Rock of Ages has been going forever on stage, so it's a shame that their show-stopper has been hijacked by TV Sensation Glee, and Journey's song has now become the definitive sound of the 80s.
Meanwhile, the producers have somehow transformed what was a horrible, grasping, capitalistic decade into a sweet, colourful, nostalgic piece, where the homely Oklahoma values sneak out and triumph over the bedlam and debauchery of the Strip, even while it is the Strip's very debauchery that is at risk in the high stakes part of the film, and whose survival is call for euphoric celebration. None of this, of course, adds up, but hey, it means antagonist Catherine Zeta Jones ends up sneaking in, dressed up like one of those female "musicians" in a Robert Palmer video. What's not to like?
This is not a film that's meant to be judged, or if it is, judged extremely harshly - Russell Brand really isn't acting AT ALL - and then enjoyed anyway. It's like listening to all your guilty pleasures in one secret iPod session on a rainy afternoon. By the time you've come to your senses that any one track really is objectively unlistenable - Zoom! is one such contender - it's time to lift the stylus and put it down on the next one. And by the time you throw in the towel and find yourself going "Oh, Scorpions... excellent," you know you've been got.
It's Hairspray with knobs on. And it's going to make a fortune.
Rock of Ages is in UK cinemas on 13 June. Pictures of the stars, and trailer below...