It's not uncommon for a band to shift personnel every once in a while, but one thing a band rarely survives is the loss of the primary songwriter. However, sometimes a band overcomes this loss and continues making music, and as these six bands proved, this can either an improvement or a horrible mistake.
Though the Misfits rotated through a number of musicians during its initial run, the band was essentially a songwriting outlet for lead vocalist Glenn Danzig. After Danzig left the band in 1983 to form Samhain, the Misfits were understandably finished, but that didn't stop bassist Jerry Only and guitarist Doyle Wolfgang von Frankenstein (not their real names, obviously) from reforming the band without Danzig in 1995. Though the band would release more albums with this new line-up than it did in the '70s and '80s, many fans (myself included) don't consider a Misfits album without Danzig to be a true Misfits album.
2. The Velvet Underground
In my article on bands whose final album was its worst, I mentioned the Velvet Underground's Squeeze from 1973, which was written and recorded without a single original member, including primary songwriter Lou Reed. Though Reed had become fed up with the band and left during the recording of the classic Loaded album in 1970, the band's manager Steve Sesnick allegedly coaxed bassist Doug Yule into touring and releasing an album under the Velvet Underground name, which lead to the forgettable Squeeze.
3. Depeche Mode
Though Martin Gore has been a member of Depeche Mode from the beginning and is widely known as its primary songwriter, the band's earliest songs were actually written by Vince Clarke, including the huge single "Just Can't Get Enough." However, when Clarke left the band in 1981, he left Gore to step up as the primary songwriter, taking Depeche Mode to its darkest and most successful years.
4. The Sex Pistols
Sid Vicious may be the Sex Pistols most famous bassist, but the band's best was founding member Glen Matlock. Though guitarist Steve Jones disputes the extent of his contributions, Matlock served as the Sex Pistols' primary composer, until he left the band in 1977, and was replaced by Sid Vicious. According to Charles Shaar Murray, "After they got rid of Glen, they got some great photos taken, but they never again wrote a decent song."
5. The Clash
Though the songwriters in each of these other bands left by their own volition, the Clash essentially dug its own grave when it kicked out guitarist Mick Jones, who was the band's primary composer. Singer Joe Strummer wrote one more Clash album with producer Bernard Rhodes, which was 1985's Cut the Crap, an album as critically reviled as the Velvet Underground's Squeeze.
6. Pink Floyd
Most of Pink Floyd's most famous songs are from the band's '70s era, when Roger Waters, Dave Gilmour, and Rick Wright were writing the music, but Pink Floyd's earliest songs with original singer/guitarist/songwriter Syd Barrett sound much different. Though Barrett brought the band mainstream success, he was mentally unstable and possibly schizophrenic, which caused him to leave Pink Floyd in 1968 and drop out of the public eye entirely, until his death in 2006. It took Pink Floyd a few years to find its footing again without Barrett.