Efficiencies of Scale is a thing, as is specialization of technology. Power plants can run at near constant rpm, and power thousands of households; inspections

Efficiencies of Scale is a thing, as is specialization of technology. Power plants can run at near constant rpm, and power thousands of households; inspections of emissions equipment and practices at that site can be enforced and fixed. Versus the same thousands of cars, a few have a check engine light on, a few have a leaking oil gasket, a few have a worn out ignition system, some of them bought contaminated gas. Any parking lot oil stain disproves you.