First I'll say that I agree with you, there have been various treatments that never seemed to have made it into clinical trial and one that did make it but never became a treatment. Some where laser causing dentine to regenerate, one I remember was a certain kind of sponge filling made with an Alzheimer related treatment that would actually regenerate as the filling itself turned into dentine over time.

But what do you mean with do as your told? What do you use to clean your teeth? What toothbrush to do you use? What are the ingredients of your toothpaste?

What is the average PH of your mouth? Do you have acid reflux often? Do you eat sweet foods or flour i.e. simple carbs often? Do you eat a lot of fruits or salads before sleep?

I've had a long history of cavities until I actually started paying more detailed attention to what I eat, what tooth paste I use etc. None of that is stuff any of the dentists I went to ever told me. I panicked when a piece of my tooth broke off almost a decade ago.

BTW there is a treatment before you have to do root canals, I forgot the name, and most dentists don't do them. There is also a chance that it doesn't work and I assume that that's the reason why dentists don't generally offer it. I forgot the name but you can surely find it by googling. For a lot of people myself included don't an artificial gum transplant for receded gums also massively reduces exposure to dental issues.

There are certain calcium phosphote combinations like the Novamin thing that GSK bought and then forbade everyone else to use or Hydroxyapatite, which is sort of artificial dentine.