Steve Jobs, driven by his genius and his gut, invented the iPhone and built Apple into the world’s most valuable company. He was uncompromising, larger than life and irreplaceable. His life was creating the future, which would be filled with devices controlled by their users.

Sam Altman spent the last year taking on the mantle of Mr. Jobs as the Silicon Valley entrepreneur in charge of tomorrow. It is the biggest job in Silicon Valley, and now the most difficult. As more people worry they will be controlled rather than in control, the future is fraught with danger.

Until Friday, Mr. Altman was the chief executive of OpenAI, the dominant artificial intelligence company. He promised A.I. would usher in humanity’s first golden age even though it came from the same kind of inventors who thought there was a market for internet-connected toasters.

Mr. Altman’s vague but vast ambitions got him in trouble with the board of OpenAI, which said he was “not consistently candid” in his communications and fired him. This shocked Silicon Valley, which did everything but march to the company’s San Francisco headquarters with pitchforks to demand Mr. Altman’s reinstatement. The future is abstract, but serious money was at risk.

The attempt at a reinstatement apparently failed — this is an ongoing saga — but the last few days deepened the parallels to Mr. Jobs, who was marginalized by the board of Apple in 1985. Apple was faltering, and Mr. Jobs was not exactly a model employee. He left the company of which he was a founder and the personal computer industry he championed.

Eleven years later, with Apple even worse off, Mr. Jobs returned. It was the greatest second act in American business history. Apple is now worth $3 trillion.