"Bit oversimplified here. High performance machines generally do a few things differently like:
1. Climb faster (higher TAS - more cooling airflow)
2. Cruise higher (cooler air)
3. Climb quicker (less time to get hot)
My Aerostar, when it's hot, can't climb at anything near best angle or best rate without the CHTs creeping up."
1. It is not the TAS that cools it is the IAS
2. Higher = less air density which reduces cooling capability, not sure where the cross over of reducing OAT and air density is but suffice to say at FL's (with turbo/super charging) you will struggle with cooling
Your last comment sums it up, it is either overcooled in the cruise or under cooled for low speeds and ground ops, hence why cowl flaps were invented, you can't have it both ways.