Much of the American Christmas music tradition took root during World War II, a period that saw the release of “Holiday Inn” (1942), in which Crosby first sang Irving Berlin’s heart-string tugging “White Christmas.” It was a time when live music ruled the radio networks, giving prominence to pop-standard stars of the time, who recorded the songs that remain popular today as holiday classics. Soldiers far from home, and families awaiting their return, shared these tunes that stressed home, hearth and family. Back then, most people heard the same radio shows and saw the same movies. It was all a shared experience, quite unlike with today’s fragmented media.

The war era was a golden age of holiday spirit, not only for Christmas music, but also for the holiday films still cherished at this time of year—“It’s a Wonderful Life,” multiple versions of “A Christmas Carol,” “Miracle on 34th Street” and many etceteras. It was a time of relative innocence that many folks regard with a sense of deep nostalgia.

In the 1950s there was a burst of pop holiday creations, such as “Rockin’ Around the Christmas Tree,” “I Saw Mommy Kissing Santa Claus” and “Jingle Bell Rock.” These too are staples on the 2012 holiday playlists.

It’s hard to imagine that today anyone would write such a simplistic ditty as “Rudolph the Red-Nosed Reindeer,” which first appeared in story form in 1939 as part of a printed promotion for Montgomery Ward department stores. Ten years later, songwriter Johnny Marks—who was also responsible for “Holly Jolly Christmas”—converted it to the tune that Gene Autry would record, selling two million copies in 1949. Today, it remains an indelible favorite, the second-biggest holiday hit behind “White Christmas.”

Contemporary artists still record new holiday albums each year. Yet these contain almost exclusively tunes from the golden age. The recent release by the country-pop trio Lady Antebellum, for example, includes just one new song, the title track “On This Winter’s Night,” plus 11 covers of surefire favorites including “I’ll Be Home for Christmas” (1943), “Have Yourself a Merry Little Christmas” (1943) and “Blue Christmas” (1948).

Rolling Stone asked its readers to pick the greatest Christmas song of all time, and they came up with the more than three-decades-old “Happy Xmas (War Is Over)” by John Lennon. The same year, 1979, Paul McCartney wrote and recorded “Wonderful Christmastime” which, according to Forbes, has earned him roughly $500,000 every year since.

Despite the potential payoff, newly composed holiday music is rare. Mariah Carey’s 1994 release “All I Want for Christmas Is You” is one of the few monster holiday hits in recent decades. The song ranks highest among all digital downloads of Christmas music since 2003, but in second place is “The Chipmunk Song (Christmas Don’t Be Late)” from 1958.

A generation that wouldn’t recognize the cars, can’t fathom the fashions, and might never buy other music of the 1940s is in the shopping malls again this season, humming along with Gene Autry. Would they ever imagine that he was known as “the singing cowboy” and often performed with a guitar on horseback?

Our special fondness for decades-old holiday music seems immune to forces that change almost everything else around us. Now that’s a holly jolly thought.

(c) Peter Funt. This column first appeared in The Wall Street Journal.