For someone whose career has supposedly sunk to the bottom of the pop culture septic tank, Mariah Carey isn’t doing too badly. Sure, she got very publicly dropped from an extremely lucrative record deal signed just last April, and she’s still probably recovering from the “exhaustion” which put her in the hospital last summer. Her most recent album, released on Sept. 11, sold just 478,000 copies and cost her record company $10 million. And if that weren’t bad enough, A Walk to Remember, the highly forgettable movie debut of third-rate pop singer Mandy Moore, just earned in its first weekend nearly three times what Carey’s Glitter grossed in its entire run.

So fine. That’s got to sting a little bit. But from where I sit, Carey’s in better shape now than she’s been in for years. Besides the $49 million she earned as severance pay from her record label, Carey’s more famous than she’s ever been, more an object of public interest than anyone else in the music industry. She’s so famous, in fact, that instead of having porn advertisements sent from “Brittney Spears” filtered out of my Hotmail account, they’re now coming from “Mariah Carrey” instead. She’s also earned the goodwill of the armed forces by performing for American troops in Kosovo, and if that didn’t prove her patriotism, she performed the national anthem for a billion viewers at the Super Bowl this past Sunday.

As far as comebacks go, she couldn’t be doing much better. Nevertheless, there’s one piece of advice that Carey must remember if she’s to regain her status as the world’s best-selling artist. It’s advice that’s so simple, so straightforward, so abundantly obvious that only people in the music (and possibly movie) industry could possibly forget it: the next product has to be good.

From the first time Carey’s album sales began to drop, and certainly in the months since the disastrous Glitter, entertainment industry observers from People to the New York Times have postulated their theories about what the 31-year-old singer must do to revive her career. Some have suggested she return to the effervescent pop that originally made her a star, while others have urged her to reclaim the fully-clothed good-girl image she originally presented on MTV and in concert.

While the insiders are probably on to something with all this talk about “image,” they seem to be forgetting the key element behind what makes a singer successful. Even in this dark time of ’NSYNC and Enrique Iglesias, singers still depend on their music more than anything else to sustain album sales and fan support. Entertainment critics talk endlessly about Madonna’s miraculous ability to “reinvent” herself and her music, but although her various costumes and public romances have helped to keep her in the spotlight, she’s ultimately stayed there because her music has remained interesting and memorable. “Like a Virgin” might not work so well if Madonna were to release it today, but it’s ludicrous to argue that her success is due to a cone bra, cowboy hat or kimono.

The same logic applies to the rest of the current set of singers, lip-synchers and ambiguous go-betweens. Despite the reported $30 million Michael Jackson spent to hype his recent Invincible incarnation, the album failed to attract young listeners because it was one song deep. Though naysayers wishfully forecast doom and destruction for Britney Spears and the rest of the teen pop movement, she and ’NSYNC continue to outlive the predictions. Why? Because as savvily packaged and heavily promoted as they may be, their songs remain danceable and fun. Jessica Simpson and the Backstreet Boys are drifting toward oblivion not because the concepts for their music videos are worse, but because their music is.

Carey, who no doubt considers herself a more serious artist than Spears and ’NSYNC, can look elsewhere in the industry for confirmation of this argument. With her sophisticated and distinct Songs in A Minor, Alicia Keys materialized unexpectedly to release one of last year’s most successful albums. No Lolita-inspired appearance on MTV was called for; the music sold itself. A brief look at the rest of the Billboard 200 proves the point; whether it’s country, hip hop, rap or rock, the music inevitably transcends, or betrays, whatever image the artist is trying to present. After more than a year on the chart, the bluegrass/country/gospel soundtrack to O Brother Where Art Thou? is hovering just below the top 10 (key term: bluegrass!).

Consequently, Carey is faced with quite a task. Because difficult though it may be to pick the right combination of bikini and high heels for her next video, her future actually rests on her ability to create more of the catchy pop tunes (or heaven forbid, goopy ballads) that launched her career a decade ago. As her last album proved, making that type of music isn’t always easy to do. Her fans have not proven themselves loyal to Mariah Carey, superstar and prima donna; to win them back, she’ll need to reinvent Mariah Carey, musician and singer.