Why the Toyota Prius rules the road despite 15 years of competition

This week marked the passing of a car that could have been a contender, as Honda announced that it would halt production on the Insight Hybrid. Though the Insight debuted in the U.S. in 1999, months ahead of the Toyota Prius, Honda sold fewer than 300,000 in the intervening 14 years, nearly half of those in Japan. For most of its existence, the Insight was a speck in the rearview mirror of the Prius, which has sold to more than 3 million owners in the same time.

The Insight was the only car on the market that seriously tried to challenge the Prius on its own turf, a hybrid designed as such. All the other manufacturers have futzed out, putting a hybrid drivetrain into an existing gasoline-powered model. The results have been unwieldy and mostly unpopular; the sole exception, Ford’s C-Max Hybrid, came to market a decade too late and is inferior to the Prius in every way that counts.

When it comes to hybrids, the Prius stands alone; no other single vehicle so dominates its competition. In 2013, the three members of the Prius “family” outsold all other hybrids from all other manufacturers combined. The Prius liftback sold almost four times more than the top-selling hybrid from a company other than Toyota — the Ford Fusion — and in California, it was the top-selling car, period.

But is building hybrids really so difficult that only Toyota can get it right?