Paul McCartney is a major boomer bridge for Coachella

If you need proof that the generational divide that has defined American pop since the rock era is vanishing along with the rock era itself, look no further than the top of the bill for this year's Coachella Valley Music and Arts Festival: Paul McCartney headlines the main stage Friday, April 17. (The other listed name likely to cause maximum excitement belongs to Leonard Cohen, the 74-year-old Zen grandpa of the singer-songwriter clan.)

For most of its first decade, Coachella celebrated the indie-to-alternative sounds and styles that came after punk slapped down classic rock and gave the new kids their chance to lead. Sunday night's headliner, the Cure, is a nostalgia act for the alt-rock generation, while Saturday's mainstage closers, the Killers, is its idea of a classic rock band.

In the past, the top of the bill has been dominated by artists who, while not completely rejecting the influence of their elders, signaled the rise of a new generation, with new social and political concerns and an affinity for hip-hop and electronic music. Last year's appearance by Pink Floyd honcho Roger Waters began to alter that script.

Coachella founder Paul Tollett wanted to open younger ears to the music of an elder he appreciates, but he also must have known that Waters' success would help convince his peers that this was a safe event for them to play. Featuring legacy artists also helps break down the old idea of rock as youth music and makes it an intergenerational affair.

Baby boomer favorites rake in major profits on the touring circuit. That's one reason why Tollett booked the Eagles to co-headline Stagecoach, the "country Coachella," last year. While middle-aged rock fans are suffering the blows of the economic crash along with everyone else, they're more likely than most to save up for a big entertainment splurge featuring an old favorite. And they might be more familiar with layaway plans, like the one the fest just introduced.

McCartney defines the old-favorite category, as well as the cross-generational one: This year we'll probably see a whole crop of high school and college kids darting around the polo grounds trying to shake off their parents. Macca's recent releases, including the feisty 2007 solo album, "Memory Almost Full," and last year's installment of electronic project the Fireman -- at Coachella, he'll play selections from the Fireman's "Electric Arguments," which has earned him some new young fans -- have helped lighten the heavy burden of his Beatleness.