Silly or not, the question of what would have happened if the Beatles hadn't succeeded - if they had, say, failed their 1962 audition with producer George Martin at Abbey Road studios and gotten stuck playing to lunchtime crowds at the Cavern Club - leads to more essential ones.
Why did the Beatles not only make it, but make it in the scream-inducing, culture-quaking, ultimately enduring way that they did?
Why were John, Paul, George, and Ringo the ones to set off a global pop culture revolution? What made them able to pave the way for an entire "Invasion" of British bands, and also silence naysayers who still held that the Elvis Presley-Chuck Berry rock-and-roll explosion of the 1950s was nothing more than a fad fueled by delinquent teenagers?
In short, what was so special about the Beatles that Americans simply could not resist them - and still can't?
In 1964, the first Sullivan appearance drew 73 million viewers, the biggest TV audience ever at that time, even though as recently as November 1963 the four Liverpudlians had been virtual unknowns in the United States. A generation later, their greatest-hits set, 1, was the biggest-selling album of the '00s, moving more than 11 million copies.
It has to do with talent, of course: The contrarian at the bar who claims the Beatles stink is not to be taken seriously.
But that's only part of it. If being good was good enough, then "She Loves You" would have become a smash the moment it was released in September 1963 by Philadelphia label Swan Records. Instead, it failed to chart, and scored only 73 out of 100 with Philadelphia teenagers on American Bandstand. Dick Clark later said: "I figured these guys were going nowhere."
Nope, it took more than talent. Timing was important - in March 1964, "She Loves You" finally did go to No. 1 and was No. 3 in April when the band held all five top spots on the Billboard Hot 100.
But that was only after a series of events had occurred - including the assassination of President John F. Kennedy - that helped turn Beatlemania into an unstoppable force.
There were other contributing T's. Tenacity, for one, and toughness. By the time they arrived in the U.S., the Beatles were road-hardened entertainers who had honed their chops playing around the clock in the rugged port cities of Liverpool, England, and Hamburg, Germany.
They were massively ambitious. "Where are we going, Johnny?" McCartney and George Harrison would ask their leader, to cheer each other up when they had no gigs or prospects. "To the toppermost of the poppermost," John Lennon would reply.
Technology had something to do with it. Playing three weeks on the Sullivan show, a deal shrewdly negotiated by manager Brian Epstein, gained them unprecedented exposure.
But another overlooked innovation came into play. As Billboard pointed out in a story titled "The Beatles: The First Viral Sensation," "the transistor radio was the technological spark that lit the fuse of teen culture in the '60s." Ten million transistor radios were sold in 1963. The iPods of their day were the must-get gift for Christmas in 1963, the day before Capitol released "I Want to Hold Your Hand" as a single.
One more T: Tenderness. To the millions about to be swept up in a sexual revolution - Betty Friedan's The Feminine Mystique was published in 1963 - the working-class quartet were innocent and sweet-seeming, in matching suits and skinny ties. "The Beatles wore the white hat," Keith Richards has said. "What was left? The black hat."
Also not to be underestimated: They were funny. George Martin was intrigued by their songs, but impressed by their Liverpool wit, nurtured by enthusiasm for The Goon Show, the British radio hit featuring Peter Sellers, whom Martin had produced.
When the four friends met the press at newly renamed JFK Airport, the Fourth Estate aimed to mock, and ended up smitten. "Are you for real?" they were asked. "Come and have a feel," John suggested. The romance was on.
That they were a great live band is evident on On Air: Live at the BBC, Volume 2, the charming new collection of 37 previously unreleased radio performances. Further proof is a scream-free concert recorded in Stockholm in October 1963 that circulated on YouTube last month.
The Beatles arrived as the country was desperate for a lift after the shock of the Kennedy assassination. Plus, they validated American pop culture by selling it back to the Yanks, using rock-and-roll and R&B as their source material.
But after that initial explosion, their endurance is due to their rapid growth as artists who shaped, and were shaped by, the tumultuous times. That development can be traced on a newly issued boxed set, The U.S. Albums, that collects the music that was sold to U.S. fans. Often with different titles and inferior track listings than in Europe, they nonetheless hold a special place in the hearts of fans of a certain age who experienced the band through them for the first time.
To revisit the Beatles catalog is to remember all that made them extraordinary. All four members sang lead. They embraced evolving studio technology (and mind-expanding stimulants) with trademark creative restlessness. In addition to two incomparable songwriters, their other very good one also was an ace lead guitarist.
In the end, the Beatles' endurance - among baby boomers, and their children, and their grandchildren - boils down to the strength of their front men's songs. "You know, I was in one of the great collaborations of all time," McCartney said in that 2005 Inquirer interview. "The both of us were phenomenally lucky to have found each other. I was a foil for John, and he was a foil for me."
In the On Air notes, McCartney recalls the "spirit and energy" of the Beatles, and stresses their drive to succeed. But he also hastens to add one last salient point about why we're still fussing over them, 50 years after the fact.
"By the way, of course, we were brilliant! Let's not forget that. I always say to people, 'Not a bad little band.' "
TELEVISION The Night That Changed America: A Grammy Salute to the Beatles
8 p.m. Sunday on CBS3.