When an artist is popular and makes a good living, he can't be playing jazz, his music must have a qualifier; like "soul Jazz".
Grover Washington was popular, and his music was "jazz" without any qualifier. All jazz musicians in the past have given their versions of popular tunes without getting the title of "soul jazz musician"; whatever, as long as he was able to take it to the bank.
Here are two of my favorite tunes by Grover:
http://www.youtube.com/watch?v=i80HVojYPdA
http://www.youtube.com/watch?v=hUFd3c2HZvI
Enjoy the music.