Apple and Amazon got so big because they piggy-backed off of larger movements in tech and culture—the shift of attention to mobile and the shift of retail to the Internet—that created enormous new markets for them to dominate. Investors expect Tesla to dominate the electric future of cars the way Apple gobbles up smartphone profits and Amazon dominates e-commerce.

But the future of cars is a riddle within an enigma, as the industry sits at a crossroads facing several divergent futures—driven vs. self-driving, private vs. shared, gas vs. electric. Here are three questions that will shape the future of cars.

1. Will people drive cars, or will the cars drive themselves?

The self-driving revolution is like a massive West Coast earthquake—experts claim it’s practically inevitable, but nobody can say for sure when or what it will look like. Business Insider Intelligence predicts there will be 10 million self-driving cars on the road in three years. In 10 years, about a quarter of miles driven in the United States could be in self-driving electric cars, according to Boston Consulting Group.

If this self-driving future never fully materializes, legacy car companies will probably benefit from the lack of disruption. But is it so obvious that they would also lose, even in the self-driving scenario?

To be sure, investors are betting against them. The price-earnings ratio—a company’s share price divided by its earnings per share—is a barometer of investors’ optimism in future profit growth. The average P/E for the S&P 500 is in the mid-20s. But the ratios for car companies, like Ford, GM, and Toyota, are all around 10, which suggests that investors aren’t confident that their profits will last. (Tesla has no P/E ratio, since it has no E.) Musk is preparing for the autonomous future by installing self-driving hardware in all of his new cars. This way, when Tesla finally acquires or develops the software for fully autonomous driving, cars bought this year can be retrofitted to drive themselves.

Earlier this month, Navigant Research published a report that declared the worldwide leader in self-driving tech is Ford, followed by GM, Renault-Nissan, Daimler, and Volkswagen—all car companies. Tesla finished 12th. One research report isn’t gospel. But it suggests that the “Tesla Is Apple, and Cars Are Smartphones” thesis has some serious limitations. In 2007, Apple’s competitors thought the iPhone was a terrible idea. But in 2017, almost all of Tesla’s competitors are engaged in a global race to build electric and autonomous vehicles, and some of them are arguably ahead of Musk in software and distribution capacity.

2. Is the future of cars electric, or something else?

The simplest story about Tesla goes like this: It has the best technology, by far, and strongest brand, by far, in the auto market’s largest growth sector.