Elon Musk, Tesla’s chief executive, has made plenty of bold predictions. They don’t always come true. On Monday, Mr. Musk said the company was on the cusp of making cars that could drive themselves safely on any road. He also promised that the company would begin operating a fleet of driverless “robo taxis” by the end of next year. “I’m very convinced,” Mr. Musk said in a presentation to analysts at the company’s headquarters in Palo Alto, Calif. “In the future, people will want to outlaw people driving their own cars because they’ll be unsafe” compared with autonomous vehicles. Many auto executives and analysts think Mr. Musk is being wildly optimistic and say cars that can drive themselves at all times are at least several years away. “The idea that you can have a vehicle that can make complex decisions for full self-driving is just not plausible at this point,” said Mike Ramsey, a Gartner analyst. If Mr. Ramsey is correct, it wouldn’t be the first time Mr. Musk has gotten ahead of himself. The chief executive once forecast that Tesla would make 500,000 cars in 2018, but it produced half that many. Last summer, he said Tesla would make 10,000 Model 3 sedans a week — about twic...