Also, when you have an event largely centered around the consumption of alcohol--and that's what Food & Wine is--I can understand a desire to cater to those in their 30s and 40s rather than those in their teens or even college years. For a host of reasons.
This is pretty much it.
2008 is when they got their act together regarding the concerts and figured out their target audience.
Here is 2007's artist list (from the archive here)
Sept. 28-29 -- Al Stewart
Sept. 30-Oct. 1 -- Otis Day and the Knights
Oct. 2-3 -- The Beach Boys
Oct. 4-6 -- The Original Family Stone
Oct. 7-9 -- Sheena Easton
Oct. 10-13 -- Starship featuring Mickey Thomas
Oct. 14-16 -- David Cassidy
Oct. 17-18 -- Little Richard
Oct. 19-21 -- Juice Newton
Oct. 22-25 -- The Four Tops
Oct. 26-27 -- The Village People
Oct. 28-30 -- The Outlaws
Oct. 31-Nov. 3 -- Jon Secada
Nov. 4-6 -- Chubby Checker & The Wildcats
Nov. 7-8 -- The Contours featuring Sylvester Potts
Nov. 9-11 -- David Sanborn
And here is 2008:
Sept. 26-27 Big Bad Voodoo Daddy (NEW) “You & Me & The Bottle Makes 3 Tonight (Baby)”
Sept. 28-30 Sheena Easton (2 Grammys) “Morning Train (Nine to Five)”
Oct. 1-4 Starship starring Mickey Thomas “We Built This City”
Oct. 5-7 En Vogue (NEW) “Hold On”
Oct. 8-9 Jonny Lang (NEW, 1 Grammy) “Lie to Me”
Oct. 10-12 Peabo Bryson (NEW, 2 Grammys) “If Ever You’re in My Arms Again”
Oct. 13-14 Sister Hazel (NEW) “All for You”
Oct. 15-16 David Sanborn (6 Grammys) “Lesley Ann”
Oct. 17-18 Jon Secada (2 Grammys) “Just Another Day”
Oct. 19-21 Spyro Gyra (NEW) “Morning Dance”
Oct. 22-23 Otis Day & the Knights “Shout”
Oct. 24-26 Exposé “Point of No Return”
Oct. 27-28 Kool & The Gang (1 Grammy) “Celebration”
Oct. 29-30 Boyz II Men (NEW, 4 Grammys) “End of the Road”
Oct. 31-Nov. 2 Atlanta Rhythm Section (NEW) “So Into You”
Nov. 3-5 David Cassidy “I Think I Love You”
Nov. 6-7 Night Ranger (NEW) “Sister Christian”
Nov. 8-9 Los Lobos (NEW, 3 Grammys) “La Bamba”
From there on out it has been geared more and more to people born around 1980-ish.
It's pretty obvious the demographic they either draw or want at Food and Wine.