They haven't got old yet.

And neither has "Quadrophenia," The Who's other rock opera, the one that isn't "Tommy." Saturday night in Marine Midland Arena, this less popular brainchild of Pete Townshend seemed just to be coming of age.

The story of crazy Jimmy, a schizophrenic times two — quadro — makes for an odd story of multiple characters who all happen to be the same guy, except that in this show they’re Roger Daltrey, Townshend, Gary Glitter and Billy Idol. Barely stopping for breath or applause, the music and videos and movie clips ascend to a true show biz extravaganza, worthy of one of the world’s greatest rock bands ever, and reason enough for the near-capacity crowd to leave the building screaming.

Townshend always has been a rock oddity, the mad genius of the music who took everything way past its limits before anyone was sure what they were. He created some of the most innovative sounds ever to be ripped out of a guitar, then leapt on stage to windmill the music to a pulp before smashing that same guitar to kindling.

There was little windmilling and no smashing Saturday, not because Townshend’s talent is showing its age (only his body is doing that). He’s just already done that.

REVIEW The Who

Rock ’n’ roll icons perform the rock opera “Quadrophenia.”

Saturday night in Marine Midland Arena.

On the opposite side of the stage, John Entwistle held a special court of his own. He stepped into the spotlight briefly, to show close up (via the backstage screen) how well his hands work, almost independently from the rest of his body, in making that bass bring home the paycheck.

But it’s Daltrey who has made the real deal with the devil. While the rest of the band declines to act its age, he refuses to even look it. His voice has a more mature sound than that of the curly-haired kid who owned Woodstock, but the curls and bravado, along with the passion, are still intact.

It’s the passion that keeps The Who and its fans alive. When a full-stage production of “Tommy” came to Shea’s earlier this year, theater-goers saw a top-notch show with talented singers and innovative staging. The music was good, and when it was over, no one in the audience cared a lick about any character they had just seen.

Not so when Daltrey and Townshend are around. For them, “passionless” is not a possibility.

Townshend may be the most forlorn looking genius in rock ’n’ roll, but he’s also a demanding one. As long as he and the boys were going on the road, they were going to do it right.

That meant bringing along Pete’s brother, Simon Townshend, on lead guitar. He was so perfect you wonder why he wasn’t with the band all along. Zak Starkey — Ringo Jr. — was on drums, and there were other less-well-known names holding up the rest of the back-up roles.

Then there were Gary Glitter and Billy Idol, the old and young Elvises of the show.

Glitter appeared first, singing Jimmy while dressed as a leather and rhinestone cross between Mad Max and Tammy Faye Baker. Heavy and heaving, he put all he had behind the mike and let it go, a showman ham without the can.

In counterpoint was Idol, sneering and leering through a juicy strut as the bellboy from hell.

But in the end, it was the Roger-Pete-and-John show. All through the night, you kept thinking the stage was going to explode, then they just about did it, with Daltrey shrieking “rain on me,” and the light catching his supplication in eerie silhouette.

And that was it. A three-song encore, a few quick introductions, a few “it’s great to be in Buffalos,” and they never had to ask the fans how they were doin’.

They knew. For a bunch of rockers who once thought people tried to put them down, it was very good, for everybody.