Because most vehicles have a pressurised liquid cooling heat transfer system bolted in at the factory and a refrigerant cooling system.

HVAC in automotive and industrial machines is a solved problem. I don't know why you would think otherwise.

Because it's not a solved problem.

Could have fooled me. I work with industrial machines and kilowatts of electronics, it's all fairly low maintenance.

1000 watt isn't really that much heat to deal with.