If it makes you feel any better...
Our little furry bastard has been free-bowled since he was 3 months old, with Costco dry food, with a small can of wet food in the evening as a treat. Now he's a healthy happy 10 year old cat, in good shape. Except for one scare, not a single medical issue.
Cats are pretty dang resilient, and juts like humans, some have sickness already in their genes, and most don't. Free bowling with dry food, clean bowl of fresh water always available, and once a day scooped litterbox -- and that's it? Oh yeah, pets on their head and a scratch behind the ear and under the chin, and a warm lap to sleep on.
I think the trick is to find the dry food that the cats will eat, but don't love -- so they will eat it when they are hungry, but don't gobble up the whole bowl in a sitting. This way they will not be overweight. But again, maybe that's mostly genetics.