The Secret Tesla Motors Master Plan (just between you and me)

Musk laid out a deliberately sequenced plan for Tesla: first build an expensive, low-volume sports car (the Roadster) for buyers willing to pay a premium, use the money and credibility from that to fund a medium-volume, lower-priced car (which became the Model S and Model X), and use that to eventually fund a high-volume, affordable car (the Model 3) — with the explicit end goal of accelerating the world's transition away from a 'mine-and-burn hydrocarbon economy' toward solar-electric energy, not just building cars for their own sake.