The the album Bitches Brew that introduced a

The role of the musician in the creation of their art does not change
fundamentally. The size of the ensemble, the instrumentation, the
arrangements, improvisations, volume, styles, rhythm patterns etc. may
vary but the artist remains the creator or interpreter of that art. 
 When rock & roll burst on
the scene of popular music this new genre proliferated throughout this
country and much of the Western World sowing its own seeds of the new
style. Since jazz is essentially about musical freedom and
interpretation, it was natural that even some of the most recognized
artists allowed those seeds from the work of their rock & roll peers
to find fertile ground in jazz. Many prominent jazz artists began to
adopt and adapt elements of the new and wildly popular art form into
their own compositions and performances. Some embraced the energy of
rock and the use of electric instruments. Some remained “purists” and
continued perform in the original styles of bebop, swing and Dixieland.
In 1969, Miles Davis released the album Bitches Brew that introduced a
“fusion” of jazz and rock. Many in the traditional jazz community were
appalled but the record introduced jazz to a huge, non-traditional
audience and is still finding new fans today. Miles Davis was among the
first to record using electric instruments that perhaps helped to
enhance the appeal of his music, jazz-fusion, to fans of rock & roll
even to this day.
I do not think that jazz was or
will ever be truly at risk as an art form as long as musicians exist who
feel and express the freedom of their art through improvisation and
composition. In the 1960’s rock bands like The Beatles eclipsed jazz
popularity but the jazz itself did not disappear. Some jazz artists
embraced elements of rock that appealed to their own artistic visions
and fused them with their music. Some remained “purists” and continued
perform in the original styles like bebop, swing and Dixieland as many
do to this day. The creation of art is as ever up to the individual
artists. They choose to be influenced by new information or not. It can
be argued that the evolution of jazz represented by Miles Davis’ Bitches
Brew actually contributed to the survival of jazz because it drew a new
audience that was then inspired to explore other more traditional jazz
offerings.
Jazz will exist as long as there are musicians who create and perform it and listeners who enjoy it.