We could ask ourselves that a thousand times and bemoan that it's a shame (and it is), or we could enjoy it when they do come around -- albeit on a smaller scale -- and blow us away anew.

Such was the case with Joan Jett and the Blackhearts, who played two sets at Hersheypark Amphitheatre yesterday, the first to a packed house.

Taking the stage in black vinyl bustier and black leather pants, her three-piece band matching her spiky hairdo for spiky hairdo, she cranked out "Bad Reputation" with a wicked sidelong grin, looking tautly fit and attractive, especially when she smiled.

She followed with the Runaways' driving "Cherry Bomb," a melodic "You Don't Know What You Got," and an ironic "Do You Wanna Touch Me," her voice at once coolly seductive and threatening.

At set's midpoint, Jett showcased material from her latest album, "Sinner," which hung perfectly with any of her classics -- "Naked" (which she called "introspective"), the political commentary "Riddles," and a spry and apt "Androgynous."

She dropped in "Love is All Around" (better known as the theme from "The Mary Tyler Moore Show") for a lark, then went back to the new album for "100 Feet Away" and a sinister, dark and sexy "Fetish."

Her straightforward songs continue to suit her unaffected, clear voice perfectly.

Jett calmly dropped in a more uptempo take on her No. 1 hit "I Love Rock 'n' Roll" before closing with a thrashing "Crimson & Clover" -- which was equally sweet when it had to be -- and a punchy "I Hate Myself For Loving You."

With a little more than an hour to go before the next show, she returned for a two-song encore -- her wry version of Sweet's "AC/DC" (which joined glam and punk in beautiful wedlock) and a version of Sly & the Family Stone's "Everyday People," showing her prowess at picking cover songs that she can confidently make her own.

There's a reason Jett was a big part of last year's Vans Warped Tour -- she's the elder stateswoman of punk who showed it's entirely possible to make the genre palatable to a larger audience.

But on her own, she proves she's as valid as she ever was, looking half her age and sounding it, too. Rock on.