David Byrne, the former Talking Heads singer, gets mad when journalists quiz him about the quartet's messy demise. Richard Ashcroft, the former Verve singer, regularly pans his estranged band mates as faceless session men lucky to have toiled in his shadow. Promoting his debut solo album, the former Pavement vocalist Stephen Malkmus recently dismissed the rest of the group as an interchangeable, expendable, rhythm section. Translation: "I'm the artist here and I don't need a bunch of hod-carrying makeweights hogging my limelight." Critics and fans don't always see it that way. Byrne's latest effort, Look Into The Eyeball, is garnering indifferent reviews and modest sales.

Ashcroft's post-Verve offerings precipitated a spectacular plunge in credibility. Once lauded as a guitar-toting subversive, he is today lumped with slipper-wearing antediluvians such as Sting and Elton John. Although Malkmus's eponymous outing received quiet praise, nobody is claiming it approaches the quixotic brilliance of Pavement's first two albums.

Underwhelming solo careers - strewn with debilitating mid-life angst, bloated vanity projects and plodding rehashes of old ideas - litter rock's annals. Why do talented, trend-savvy individuals such as Byrne and Ashcroft stumble into mediocrity when granted the freedom they have so loudly craved? Could it be that the group aesthetic provides an essential, indefinable vibe, cossetting fragile egos from vain glory and self-doubt, and stoking their creative furnaces?

Crippled by writer's block, Neil Hannon of The Divine Comedy last year reappraised his attitude to collaboration. Loosening his dictatorial grip on the band, he began to treat his fellow players as partners rather than a perfunctory backing ensemble. Reviewers hailed the resulting album, Regeneration, as The Divine Comedy's must accomplished effort yet. "I feel liberated from the extreme stress and neuroses of the past albums, and I think this is the way forward for the band," Hannon told The Irish Times.

Holidaying in the alternative-rock Mecca of Chicago, the Frames singer Glen Hansard laid down the clutch of tracks that would form the kernel of For The Birds, his group's triumphant comeback record. But he resists the temptation to go it alone, claiming the "us against the world" mentality fostered by the conventional band format invigorates his writing.

"I love being in my band. I don't have any desire to go off or anything," he said recently. "I enjoy playing on my own, but it's definitely a different thing. When I play on my own I can take things anywhere I like. Whereas, when I'm playing with the band, I have to be aware of how people can feel if I take it anywhere I like."

There are exceptions. Lou Reid languished in cult obscurity until he jettisoned Velvet Underground. Kristin Hersh has seen her record sales climb exponentially since calling time on Throwing Muses. And who except a smattering of diehard aficionados has anything good to say about the Sugarcubes since Bjork went solo?

Of course, such artists are instinctive collaborators. Bjork has always sought out credible avant-garde producers. Reid's best output bears the imprint of sparring partners such as David Bowie, who oversaw Transformer, his breakthrough LP. Hersh's biggest hit featured Michael Stipe, the REM singer, on guest vocals. The New York songwriter Stephin Merritt, leader of gothic urbanites The Magnetic Fields, has taken the collaborative ideal to unparalleled extremes, putting out albums of his compositions sung and performed by other musicians.

But then it's easy to reinvent yourself when nobody has ever heard of you. Artists of Byrne's stature suffer because they want to leave the past behind, while fans crave more of the same. Retreating to the lucrative anonymity of the studio has become a popular escape route for overexposed singers. When the American power-pop outfit New Radicals disbanded in 1999, frontman Greg Alexander recast himself as songwriter and producer for hire.

Alexander ditties have since graced the top of the charts courtesy of Ronan Keating, Texas and Rod Stewart. Andy McCluskey of Orchestral Manoeuvres in the Dark this year scored his biggest hit as songwriter and Svengali to Atomic Kitten, the teen pop trio.

"There comes a point where you have to say: if I'm staying, I'll take a step sideways," says McCluskey. "It's just that sometimes egos won't allow you to do it. What happens then is that you sail into the sunset being the only person unable to see the 'sad bastard' note on your back."

Look Into The Eyeball is on Virgin; David Byrne will be interviewed in Weekend on Saturday