Healthy teeth have a lot to do with genetics too. I’m a once/day brushed (with a powered brush) and never flush unless something’s stuck in my teeth and I don’t get cavities or have other teeth and mouth problems. My wife brushes twice a day, flosses, and uses mouth wash, and has had 12 root canals, and has cavities 25% of the time she gets her cleanings done.
There are two other main differences between us. She loves sugar and I’d prefer anything salty. I’m sure this isn’t helping her and is helping me since sugar is our mouths’ enemy.
Some times but not most, like Windows. macOS is the same way thanks to its *nix underpinnings. I honestly can’t remember a time I ever reinstalled the system to fix a problem.