I think you may be onto something here, Bernina. Kind of like how they don't want to give us too many antibiotics because we become resistant to them and they don't work? My son had a black lab hat supposedly had heatworms. After the initial treatment he never gave him monthly pills, and the dog lived a healthy, hairy life for at least another ten years. Did he really have heatworms? We don't know.
I kmow when my kids were little our dogs rarely had any problems, lived a good 15 years or more, and fleas were easy to get rid of with baths, and occasionally a flea collar (I have heard too many bad things about the, so hesitate to try them now ..... does anyone use them, and if so, what brand?). Now, it seems everyone's dog has skin issues, or food into,erances, or allergies, or other maladies that are costly. I wonder sometimes if it is the food.... we used to give all our dogs basic Purina and nothing else. Now the vets want us to feed pricey prescription foods that I cannot afford. Have we bred all their tolerance out of them?
The only shots my dogs get are their rabies because that is required to get their licenses. I do use liquid flea/eggs med occasionally, but not every month. Overall, except for one instance of bladder stones in one dog, we have not had issues.
BBM
I'm would wager that if you could go back in a time machine and compare the list of ingredients for Purina dog food from what it was back then to what it is today, it would be very different.
During the last 20 years or so, companies have become so focused on profits, to the detriment of maintaining the integrity of their products.
Cheaper ingredients have become the rule. Not just with pet food, but with people food, too. That's why I stick to "whole foods" (not referring to the store, but in terms of ingredients).
Sometimes when I'm hungry or lazy or just want something fast, I'll peruse the frozen food aisle. But after reading a half dozen lists of ingredients on those packages, I just say, "no." On those rare occasions that I do buy a frozen meal, I invariably regret it. They don't taste anywhere near how nice they look on the packaging.

And seriously, if I wind up buying a pound of grass-fed beef and some artisan bread rolls, it's still only about $10, and will provide 3-4 servings.
Saturated fat, yeah. I'm okay with that. It can't be any worse than all the chemicals and artificial ingredients in frozen foods. Plus, red meat provides many essential amino acids and B vitamins. I'll take my chances. And, it actually tastes good!

ETA:
I am also very much against flea collars. We had an adorable Cavalier King Charles Spaniel that was almost catatonic after we put a flea collar on her (couldn't walk, was listless, etc). We rushed her to the vet and they decided that it was a reaction to the toxic elements in the flea collar. After a few days without the flea collar, she was back to her normal self, i.e., peeing all over the floors. Oh well, for a while we were so relieved that it didn't seem so bad...
