Prince Muhammad's autocratic tendencies have economic consequences, too.
He aims, ambitiously, to wean the kingdom off oil.
But investors are warned off by the capricious way he takes decisions.
Last year he locked up and seized assets from hundreds of businessmen, officials and princes in an "anti-corruption" drive that lacked even a hint of due process.
His effort to spur the private sector is, oddly, top-down.
The planned stockmarket listing of part of Aramco, the state oil giant, suffered from Prince Muhammad's micromanagement and has been postponed indefinitely.
Other grandiose projects, such as NEOM, a futuristic city staffed by robots, seem ill-considered.
But advisers dare not challenge the prince.
In countries like America, where Mr Khashoggi lived, the instinct has been to offer the prince weapons and support.
Instead, the prince's allies should make clear that he does not have a blank cheque—and that his rule would benefit from more openness.
Mr Khashoggi, a former government adviser, often said that his criticism of the Saudi regime was nasiha, or friendly counsel.
He did not consider himself a dissident and disliked the idea of regime change.
"It's just ridiculous," he told The Economist in July.
"I believe in the system—I just want a reformed system."
The Saudi regime should listen to its critics, not silence them.