Hmmm. Another piece of technology which increases the cost when buying the car, increases the cost when you need to replace it, for a marginal increase in effic

Hmmm. Another piece of technology which increases the cost when buying the car, increases the cost when you need to replace it, for a marginal increase in efficiency (up to 10% -- more likely to be ~2%, and on urban routes, I'm not betting on those gains on the highway). Just like xenon headlights, huge starter engines for fast start-stop times, complex injection systems, etc, these increase the costs of building and maintenance, for little benefit, and huge profits for the auto industry. When do we get mass-produced electric engines already?! They're not as complex as Otto engines (thus lower maintenance costs), so when do we start producing them in large scale to get lower prices?