Their job is to finance vehicles, of course they know about car reliability. Please get a grip.
If I default on my auto loan, all the credit union gets out of it is repossessing the car. They therefore need to know what the car is actually worth and have a good idea of what the car will be worth for the extent of the loan period. If they mess this up they stand to lose money, not just on my car but every car they finance, and they're a conservative financial institution that doesn't like to lose money. Getting good statistics on cars is comparably cheap. It's hilarious that you don't know how this works.