Olowokandi had a 9-yr career that was only abbreviated at the end by his relentless physical troubles (knee injuries, back injuries, foot injuries, abdominal tears, groin tears, severe hernia). It's why, disappointing as they were for a #1 pick, neither is a serious candidate for this thread's question. But they belong in the same breath. Olowokandi had over 4,100 career points and 3,400 career rebounds, and was 3 shy of 700 career blocks. Kwame had ~100 fewer career points and rebounds, each, with about 70 more blocks. They're roughly identical in terms of career production, and yet Kwame had the longer career.
There's no comparison to busts like Bennett or Oden.
Unexpectedly, the guy who looks like he is going to settle into the same bracket as Kwame and Candyman is none other than Ben Simmons. Never would have thought he'd finish as one of the Top 10 busts in NBA history.