When that era ended, so did his career. And soon after, he died at the young age of 45. Had he lived, I am almost certain that he'd be working today thanks to Quentin Tarantino, who most likely would have cast him in many of his films that so resemble the ones that D'urville Martin was a part of in the 1970's.
From Black Caesar to Sheba Baby and Blind Rage to Dolemite (which he also directed), D'urville Martin had a solid presence which shined in all of his work. He was as good as any actor working today and it's sad that the racial attitudes of the 1970's prevented him and so many other talented actors from getting major Hollywood work.
His films are still around, though, and if you happen to catch one on late night television, you will see for yourself why D'urville Martin is Not Very Famous...but should be.