There are some studies that suggest that delaying neutering can be healthier for large dogs. That being said, if an animal is intact for what ever reason, the human is responsible to control the animal’s opportunities to breed. Our boy is intact and our female went through two heats before getting spay. No pups in our house. We controlled their access to each other.
Yes, breeding should be done by people who understand as best we can, how to improve the breed, not just crank out popular breeds to make money. Breeders need to make a profit but that cannot be their only goal.
Sorry to hear about your big white companion. I grew up with a lab/ german shepherd mix and she developed a huge tumor on her side. There is no stopping our dogs from passing away, but we can try to give them longer better lives.