The lead singer is frequently the most prominent member of a band, simply because they are the main voice in the songs
This leads to them having all the journalist interest in interviews (particularly if they are blessed with a fantastic voice, or more likely looks).
The syndrome of a lead singer becoming so much bigger than the rest of the bandmates led to the NME labelling the anonymous 'others' as Sleeperblokes, after the band Sleeper:
Frontwoman (and songwriter) Louise Wener was exceedingly opinionated, not entirely unattractive and saved the music journo all that hard padding-out-the-article lark by talking for England. Any Sleeper interview was solely Louise. The Sleeperblokes were lucky to get a black and white group PR shot tucked at the end of the article.
The songwriter / singer / crazy hat wearer 'Jay Kay' from funk dullards Jamiroquai is the only member known to the general public. This has led to casual music fans (i.e. the type who would buy coffee table music like this) assuming he is a one-man act and is himself called 'Jamiroquai'.
Here is a list of lead singers who have anonymous bandmates:
Louise Wener - (Sleeper)
Nina Persson - (The Cardigans)
Hope - (Mazzy Star)
Gwen Stefani - (No Doubt)
Rivers Cuomo - (Weezer)
Gavin Rossdale - (Bush)
Huey - (Fun Lovin' Criminals)
Roddy Woomble - (Idlewild)
Paul Draper - (Mansun)
Here is a list of lead singers with bandmates who speak:
Thom Yorke - (Radiohead)
Kurt Cobain - (Nirvana)
Noel Gallagher - (Oasis