Why is it, when there is very nearly a superstar for every suburb, that these places are not bristling with blue plaques, offering bus tours round the relevant sites and opening childhood homes to the public, kitted out in period G-plan with a guitar left nonchalantly on a candlewick bedspread and a lyric scrawled in a schoolbook on the kitchen table?
I put it down to indifference and embarrassment. Indifference from local burghers, and the embarrassment of rock stars - for whom image is all - about their mundane suburban roots. Bowie even used to claim he was from Brixton. But the truth is out there, in Beckenham and in Dartford, though it took a day trip to find it.
As the train rattles off through South London you can see why these boys would disown their origins. The inner city, with its seedy shops and dubious communal houses, would have been nectar to a suburban kid.
How his heart would have sunk as the train took him out past cool and slightly-scary Brixton and relentlessly on through Herne Hill with its detached villas and wide, green, open spaces. Why, Sydenham Hill station even has a nature reserve! Then it gets really ridiculous - you get places with joke names, like Penge.
Imagine the embarrassment of taking the ultra-cool, kookie American chick called Angie, whom you met in a West End club, down this line and getting out at Beckenham Junction, with its ornate Victorian ironwork. Imagine running the gauntlet of shops selling prints of the parish church, Fabulous Creatures glass animals and "superb sausages hand-made on the premises", as you make for the pub where you run an arts lab and organised a free open-air festival.
But David Bowie did just that.
The pub - Bowie knew it as the Three Tuns but it is now the Rat and Parrot - was an obvious starting-point on my Rock the Suburbs tour. He used to run Sunday night folk sessions in the back room. After his first hit single, "Space Oddity", in 1969 he got more ambitious, and renamed these sessions an Arts Lab, where a strange hybrid of mime, poetry, art, Buddhist incantation, tie-dyeing classes and free-form jazz took place. Bowie even wrote a song, called "Memory of a Free Festival", about a multi-media event he organised here, which contains the toe-curling line, "I kissed a lot of people that day".
If this were America the Rat and Parrot, which stands behind a particularly heavy camouflage of window boxes and hanging baskets, would be called Bowie's. The menu would boast Ziggy burgers and Young American fries, and a tall glass of milk would be a Thin White Drink. Mannequins would be sporting the costumes of the Spiders from Mars.
Not so in Beckenham.
The barmaid sounded slightly apologetic as she broke it to me that they had absolutely no Bowie memorabilia on the premises. "There might have been some once," she said, "but since it was taken over by Scottish and Newcastle it got themed like this." She looked around in silence at the open-plan-but-olde-worlde place, with its customers sipping cappuccinos and eating late breakfast. There was nothing more to be said.
In between his first, isolated hit single and his emergence three years later as a fully formed rock star, David Bowie lived with Angie in a cavernous flat at Haddon Hall, a Gothic Victorian villa just north of the town centre, at 42 Southend Road. Here he wrote most of the material for the albums The Man Who Sold the World, Hunky Dory and Ziggy Stardust. Night after night, with his guitarist Mick Ronson and the rest of his band, he honed songs such as "Moonage Daydream", "Changes", "Andy Warhol", "Queen Bitch" and "Kooks". Bowie has said that the character of Ziggy Stardust, the first of many strange and compelling personas that he created for himself, was born in Haddon Hall.
But as I reach the spot, past houses so vast and set so far back that they are almost out of sight, I discover that Haddon Hall is no more; No 42 has been replaced by a block of flats and a road called Shannon Way.
In 1970, while living at Haddon Hall, David and Angie got married at Bromley Register office. If they had married at a wedding chapel in Las Vegas, their names would still be up in lights outside. But in Bromley, I found, they won't even confirm that a marriage took place.
Haddon Hall became a commune, a court in which Bowie was the ever-feted king. Over-indulgence in sex, drugs and anything else that was going, was the norm. Maybe this accounts for the fact that, on the day Neil Armstrong became the first man on the moon, David saw an alien spacecraft land in Southend Road. And perhaps mind-expanding substances fuelled his desire to get in touch with any aliens in the Beckenham area. One night he stood on the roof aiming a wire coathanger at the skies, until a golfer on the Beckenham Place Park course behind Haddon Hall yelled at him: "Do you get BBC2?" This, presumably, was a topical joke at the time.
Bowie's weirdness was not an act. There was madness on his mother's side of the family and his constant fear was that it would be visited upon him, as it had been on his half-bother, Terry Burns. Terry, 15 years Bowie's senior, suffered increasingly severe bouts of schizophrenia and was finally committed to Cane Hill Hospital in Coulsdon. He eventually killed himself by jumping under a train at the neighbouring Coulsdon South station.
Terry had a huge influence on David during his early teens, and inspired the songs "All The Madmen" on The Man who Sold the World, and "The Bewlay Brothers" on Hunky Dory.
In the days he was close to Terry, David was living at the family home, 24 Plaistow Grove, a mile or so to the west. As I walked there I reflected that it was his streak of weirdness that lifted Bowie out of the ordinary and made him a star, someone who could constantly reinvent himself. Without the strangeness, he would probably never have risen above his suburban roots.
Plaistow Grove is a tight, square cul-de-sac of terraced cottages beside Sundridge Park Station. The house next door to Bowie's old home bears a plaque which reads: "An artist lives here". An artist lived next door, too, but there is nothing to tell you so, or hint that this was the place where a nine-year-old picked up a guitar, thrashed out a Chuck Berry song, and announced to his startled parents that he was going to be a rock star.
Today, the only music comes from a pub called the Crown. "Live Duo Karma" and Mike and Beanie are among the forthcoming attractions.