Good thing about trannys and I'm gonna assume then also T-cases, is they're really good a storing evidence on how they took a dump. Whether it was a defective part that crapped out, or driver abuse where the tech can see extended high-temps, and parts excessively worn. The up-side is, if they deny your claim, you can ask to see the parts for yourself (and so can the entity you appeal to), The bad news is, if they deny your claim, and you abused it, they have the evidence
EDIT: just read the rest of your post.. glad they covered it.
As far as your contention that if the car is marketed to be "raced" then it should handle it, that's not black and white. Racing prematurely wears out parts. Doesn't matter if you're racing a Mitsu Evo with 3k miles on it, a '95 Miata with 180k miles on it, or a brand-new Porsche 911GT3, that just got unloaded off the boat. The maintenance schedule on a car that see this kind of operation is greatly shortened, and more parts need to be replaced.
An Evo that sees regular track time, should have it's motor and all other oils changed after a weekend event. A full-time track car (Evo or not) usually will need a once-yearly freshen-up on the motor, trans, t-case, plus some other critical components. It's chassis will also be turned to mush after a certain amount of time, and will be junk. We had a '70 911 pan-based GT2 car once.. Over the course of the year, the car went from a full-pan with a cage welded in, to none of the stock pan remaining, and a total tube-chassis car.
It's all about needing to "pay" if you wanna "play". You can also learn how to be a lot less violent with your car. A driving school would be good for this. You can learn to be just as fast (actually faster), while being smooth and "gentle" on your equipment. you could get twice or even three times the amount of time out of it.