Mick Jagger warned us it would be a drag and Pete Townsend hoped he'd die before he got there.

But getting old is working out pretty well for the graying rockers -- inspired perhaps by the longevity of the Rolling Stones and the Who -- who roam the amphitheaters in the summer.

In the first two months of the Post-Gazette Pavilion season, which opens Friday with the Dave Matthews Band, we've got Tom Petty (57), Steve Miller (64), Joe Cocker (64), Jimmy Buffett (61), Sting (56) and Rush's Geddy Lee (54).

As the guys at the deli would say, those are some "alter kockers."

The average age of the frontmen (and most of them are men) at the PG Pavilion this summer is just over 45. And it goes up a tad if you extract Taylor Swift and the Jonas Brothers, who are barely old enough to drive.

So, what's going to happen to the concert industry in five, 10, 15 years if these classic rockers aren't replenished by younger stars?

"With those musicians now in their late 50s and 60s, that gravy train can't keep rolling for much longer," says Gary Bongiovanni, editor of concert trade publication Pollstar. "For reasons no one completely understands, we don't seem to have developed a new generation of evergreens to replace them. I can't point to a lot of acts that I could confidently say will still be touring sheds and arenas 20 years from now ... certainly not enough to replace McCartney, Clapton, Rod Stewart, Elton, etc."

The list of top-grossing concert tours of 2007 was dominated by older artists -- The Police, Genesis, Rod Stewart, Roger Waters, Tim McGraw -- with a smattering of youngsters like Justin Timberlake, Christina Aguilera and Rascal Flatts.

This summer, there's a buzz about the Radiohead and Coldplay tours (neither of which are headed to Pittsburgh), but again it looks to be a heavy dose of the Eagles, Buffett, Petty, Bruce, Steely Dan and John Mellencamp. This follows a spring when the biggest arena attractions were Bon Jovi, Billy Joel and Van Halen. A generation younger on the summer circuit, but no spring chickens, are R.E.M., the Cure and Motley Crue. Even the reunited New Kids on the Block are pushing 40.

"The industry just isn't creating new superstars," says former concert promoter Rich Engler. "Unfortunately, all these legends, these classic attractions, they're still carrying the weight. Music was a different world back then and obviously, they created a tremendous foundation, which the new bands aren't doing these days. There are many reasons why: One being radio, and two, there's so many things to do now with the Internet, high definition. It's a faster world now."

If there's a three and four, they would be the skyrocketing price of tickets the past several years -- weeding out younger concert-goers -- and the near-demise of the record industry. Obviously, the major labels have been ravaged by illegal downloading and now by stars like the Eagles and Madonna going their own way. But it goes beyond that. When teen stars and grunge bands in the '90s started selling gold and platinum in the first week, the labels' philosophy changed from developing career artists to finding those who could move the most product in a hurry -- regardless of whether they could even play live. (What's up, Britney?)

"It has to do with churn-'em and burn-'em in the record industry," says independent promoter Brian Drusky, who previously worked for Live Nation. "It's not cultivating newer artists. You can have one hit record and if the next record's a dud, they lose interest. Look at Alanis Morrissette. She was huge. They're not cultivating artists long enough to create career artists."

Last week, indie-rock darlings Death Cab for Cutie topped the charts with their new album, and in the past 18 months, Modest Mouse, the Arcade Fire and the Shins all debuted at No. 1 or close to it. Twenty years ago, they would be the kind of bands getting a big push at commercial radio. But now they don't get the spins that would elevate them from a theater act to sheds and arenas.

"Unless you're Radiohead," Drusky says, "it takes radio and mass marketing."

The talent is there if Live Nation (on the concert side) and/or Clear Channel (its former radio parent) wants to bother.

Need a new U2 type? We already have Coldplay, but how 'bout the Arcade Fire?

A new Rush? Coheed & Cambria.

A new Fleetwood Mac? Eisley or The New Pornographers.

A young Talking Heads? Vampire Weekend.

A potent stoner-rock band? Queens of the Stone Age.

A future classic rocker? Ryan Adams.

A new Dylan? Come on, there's no such thing as a new Dylan!

But you get the idea.

In Pittsburgh the past two years, we don't even have a mid-sized outdoor venue where those promising mid-level bands can start to make the jump -- although the New American Music Union festival with Dylan, Gnarls Barkley, The Roots, Raconteurs and Spoon, at the SouthSide Works parking lot, is a nice option.

Here's one other hint -- The Jonas Brothers aren't the answer, because the teen-pop and Top 40 markets are historically fickle. Hannah Montana and the Jonas Brothers are huge now, but could be playing malls in three years. People vote for new American Idols in presidential numbers but don't always support them as live acts. Divas in the vein of Mariah and Whitney are in short supply -- and aren't generally the outdoor types. And hip-hop gets round-the-clock radio and video play but only a few, like Kanye West (who tops the Glow in the Dark tour this summer) and Jay-Z, truly translate to the big stage.

What's likely to keep the Post-Gazette Pavilion in the black this summer, besides the two Dave Matthews Band shows and the veteran acts, are the country and metal tours. The country music industry, an efficient star-making machine, has been able to break younger acts Rascal Flatts, Taylor Swift, Brad Paisley and Carrie Underwood by marketing them heavily on radio, TV and awards shows.

Metal has four days at the Post-Gazette Pavilion -- on the younger side with Projekt Revolution and Rockstar Mayhem, which is displacing Ozzfest, and on the older side with Judas Priest and Motley Crue.

The punk/emo/ska scene is still limited to just one day, as all the eggs are in the Warped basket. When there are 80 bands playing in one day, you'd think some of them could spin off into a second or even third successful tour.

But after 15 years, it hasn't happened.

"It's been tried and it hasn't worked," Anti-Flag's Pat Thetic said earlier this year. "The kids save their money and they want to go to Warped Tour. They don't even care who's playing."

Maybe when Rancid and Less than Jake become "classic" acts, that will all change.

In the meantime, it's not like the folks at Live Nation need to panic. These veterans aren't feeble -- yet -- and there is still a smidgen of time for the concert industry to rally.

"I think this is going to be more like 10 years," Drusky says of the aging headliner issue. "Jimmy Buffett is going to be touring for a while. And you still have Tom Petty and Dave Matthews. At some point, these bands won't tour every year, and it will be a bad thing for the concert industry. Most of the artists are from the '70s, and when they stop touring it could be an end to the amphitheater cycle. It looks like it's coming to that anyhow."