My oldest was 7 years, my youngest was not even a year. But do remember I have rescued, and crossed many different diseases (excluding velvet, oddly). It also depends on the fish itself. Sure, a human can live 100 years. Some only make it to 70, 80, 90... Others can make it to 100...103... Each fish is the same. You could put two fish in their own 10 gallons, heated the same, got the same water changes, same food, same conditioner, same treatment... guaranteed they won't live the same life span.
Breed for the breed, not for the money; the words any REAL breeder would understand.
You must know nothing in order to know all, for all is nothing and nothing is for all.