Wow, I have never heard of a car being too old for comprehensive coverage. And I have a 58 year old car with full coverage. Salvage/rebuilt title yes, but never age.
They dumped the fleet management company for the very reason that their mindset wasn't realistic. Always cheaper to fix than replace a vehicle, barring rust or extensive collision damage in my experience. That being based on the cost per mile driven. Look at the big fleet operators, they never think twice about repairs, they are looking for a million miles in some cases before replacing a vehicle.
Yeah, the extended warranties were wacky when we bought our last car. 3/4 years or 150,000 miles. I want 10-15 years and 100,000 miles coverage.