It's no secret that a deceased great guitarist/bassist has drawn more attention and awe/respect than those still among the living. While there is no clear answer to why this occurs, in the defense of the amazing musicians I can say that many of them created some of the most beautiful music ever recorded, presented unforgettable live performances, and influenced other guitarists/bassists who would also become renowned and revered. However it is also worth mentioning that many of them were also fairly young died at the height of their career. While in some, but not all cases, this was due to poor choices of lifestyle, it is also a testament to their skill that they accomplished more in such a short time than many could ever dream of.
A prime example of young talent, Duane Allman of the Allman Brother's Band is widely viewed as one of the greatest slide guitarists ever. His signature slide sound helped establish the Allman Brothers as a driving southern rock group, as George Kimball in 1971 described as "the best damn rock and roll band this country has produced in the past five years." While a motorcycle accident tragically took his life at the age of twenty-four, his spirit lives on in the Allman Brother's Band, in the sound created by current Allman guitarist Derek Trucks, and in every slide guitarist and fan who has a particular taste for the Allman's southern rock sound.
One of the greatest musicians ever to live, Randy Rhoads has left his mark on music both as part of Quiet Riot and as a member of the Ozzy Osbourne band. One of the pioneers of shredding, Rhoads formed the band Quiet Riot with his best friend Kelly Garni. However after releasing two Japan-only albums, Randy would leave the band to join Black Sabbath front man Osbourne to release the epic songs Crazy Train, Mr. Crowely, and many others that would not only establish Ozzy as an amazing solo artist, but would also expose Randy's classical-metal fusion ax work that has come to be a key component in the styles of many guitarists he has influenced, including current Ozzy ax man Zakk Wylde. While he died in a plane crash at age twenty-five, to every hard rock fan he is still very much alive.
-Stevie Ray Vaughan-
SRV was one of greatest guitarists ever to live, influencing the likes of John Mayer, Eric Johnson, and others who would become part of the electric blues power house. Vaughan won six Grammys before his death while on tour with Eric Clapton, but in his career he accomplished so much, being ranked as seven on Rolling Stone's 100 Greatest Guitarists of All Time list. However like any great artist, his true legacy is in what he did for music. Today we are still feeling his influence in today's bluesy-rock sound.
Burton is recognized as THE Metallica bassist and for good reason. Cliff bridged the effects gap between guitar and bass, making use of distortion and effects many of which not used for bass. His bass work helped create Metallica's famous album Master of Puppets. However on the Puppets tour, Burton was killed in an automobile accident at the age of twenty-four. However his successors would all draw influence from him as the band went on to create the Grammy award winning song One, the famous album Metallica, and the ever famous song Enter Sandman. But no matter how big Metallica became (and they've become very big indeed), the soul of Cliff Burton will always be present in every song and every album the band plays, whether he was there for it or not.
Mr. Thunderfingers was one of, if not the, greatest bassist of all time. Enwistle was the perfect balance that kept The Who together and made them the greatest live band ever. He is a prime example of a musician who got all he could out of his instrument. His technique can be felt on The Who songs Won't Get Fooled Again, Baba O'Riley, and My Generation. However Enwistle died in 2002 from a heart attack. Nonetheless his influence is present in bassists Nikki Sixx, Steve Harris, and countless others.