Coachella, Lollapalooza and Bonnaroo, the three biggest, are now highly developed brand names, with the drawing power to sell out well in advance; tickets for Coachella’s two weekends, for example, sold out in a matter of hours last week.

There is even a competing Woodstock: the Bethel Woods Music and Culture Festival, over the same anniversary weekend — which will also feature “TED-style talks” — will be held on the same grounds as the original, around 60 miles from the town of Woodstock. (The Watkins Glen site is further afield, about 30 miles west of Ithaca.)

For many concertgoers, another issue is whether the Woodstock name itself was damaged by the 1999 festival, which was marred by fires, rioting and reports of sexual assault.

“It’s not tainted,” Mr. Lang said. “’99 was more like an MTV event than a Woodstock event, really. I take some responsibility for that. It was also kind of an angry time in music.”

And then there is the corporate consolidation of the concert business, which has grown especially intense over the last few years as two companies, Live Nation and AEG, compete to book major tours. Live Nation is a partner in the Bethel Woods event.

“The industry has completely changed since 1999,” said John Scher, the veteran concert promoter who was a partner with Mr. Lang on Woodstock ’94 and ’99. “The entrepreneurial spirit of 1969 doesn’t exist anymore.”