Tesla under Mr. Musk has also established a template for what the “mobility” firms of the future must do. Chief among these is the ability to update vehicle functionality via over-the-air software updates; the addition of algorithm-driven features that offer partially autonomous operation along with the collection of data to improve those algorithms; connectivity with the consumer to provide services; and the ability for a customer to configure and purchase a vehicle online.

Tesla under new leadership, or as a unit of a much larger company, might be able to maintain what Mr. Musk has achieved. But Tesla’s survival thus far has been a tightrope act, and falling off is virtually guaranteed without Mr. Musk.

He has proved uniquely and idiosyncratically able to sustain the loyalty and fervent belief of investors, customers and employees. While Tesla has benefited from public subsidies such as consumer tax credits, federal grants, and the sale of zero emission credits to other automakers, Mr. Musk’s ability as a salesman is apparent in his success at raising private funds and sustaining high valuations. Even Tesla’s luck in buying its factory in Fremont, Calif., at a bargain-basement price from Toyota is attributable to Mr. Musk’s ability to charm Toyota’s chief executive.

Tesla owners also seem to identify closely with Mr. Musk. For the Model 3, they had to put down a $1,000 deposit, and most have been waiting months for their new cars. This willingness to commit to a purchase before the vehicle is even available for viewing has enormous value. It means Tesla spends almost no money on marketing, and it knows before building each vehicle who the customer will be and how he wants it configured. No other auto manufacturer enjoys this type of prerelease enthusiasm — and it is Mr. Musk who single-handedly sustains it. Were Tesla to become the electric car division of an existing automaker, even if its products stay strong, this pattern of advance demand commitments would be unlikely to continue.