Plagued with lousy ticket sales, this year's Lollapalooza tour was canceled yesterday, unplugging the best-known alternative rock festival in the country.

Organizers of the show, which originally came to life in 1991, said they would have lost millions if the tour went ahead as scheduled. Headliners were to include Morrissey, the Flaming Lips, the String Cheese Incident and the Pixies, with the bands performing over the course of two days. The tour was to kick off July 14 in Auburn, Wash., and more than 30 shows in 16 cities -- including a local stop at Merriweather Post Pavilion on Aug. 12 and 13 -- were slated.

"I'm in utter disbelief that a concert of this stature, with the most exciting lineup I've seen in years, did not galvanize ticket sales," said Mark Geiger, co-founder of the tour, in a press release. "I'm surprised, given the great bands and the reduced ticket prices, that we didn't have enough sales to sustain the tour."

One-day tickets for lawn seats were priced as low as $15, before assorted add-ons and service fees. At the upper end, a two-day ticket for reserved seats at the Denver show, for instance, ran for $80.

Other tours have struggled to fill seats, among them Ozzfest and reunion tours by Fleetwood Mac, the Cure and the Dead. But every summer there are stragglers, and every summer at least a few promoters will declare this summer the worst in memory. Plenty of artists, as it happens, have been selling out venues by the dozens, among them Prince, Madonna and double bills, like the one featuring No Doubt and Blink-182.

Lollapalooza's troubles might have more to do with musical trends than the health of the concert industry, says promoter Seth Hurwitz, who had booked the now-canceled show at Merriweather.

"It's genuinely an alternative-music problem," Hurwitz says. "The audience for true alternative rock just isn't that big anymore. Lollapalooza was big in the early '90s, when the scene was exploding, when you had bands like Pearl Jam and Nirvana, and it was something new and truly alternative. Now you turn on the TV and everyone is pierced. I saw 'Shrek 2' the other day, and there's scene in it where one of the characters crowd-surfs."

Also, multi-act shows are tough sells these days, Hurwitz added, because fans know they'll get a truncated set by their favorite performer. Morrissey, the former lead singer of the Smiths, who has just released his first solo album in several years, packed a bunch of mid-size auditoriums in a recent solo tour. But those fans might be unwilling to commit to a day at Lollapalooza, which can seem a little grueling by the time the marquee names hit the stage.

Yesterday's cancellation ends what had been a modestly successful comeback for Lollapalooza, which had been retired for six years before returning to the road in 2003. Some of last year's shows were canceled, but there were many successes, and tellingly, the lineup was more heavily weighted toward acts that were selling millions of albums -- like Audioslave, the closer -- than bands considered alternative.

There weren't a lot of platinum-status acts on the bill this time around. Groups with avid but relatively small followings, like Le Tigre, Black Rebel Motorcycle Club, Modest Mouse and Wilco, were the heart of the production. Had it happened, the concert would have hewed closer to the original, out-of-the-mainstream spirit of Lollapalooza. But that spirit, apparently, isn't what it used to be.