I strongly disagree and I would never, ever try to talk anybody out of having a much needed dental done. Nobody should. I do mean that. Nobody. Not fair to the poor cat that is in pain. Also, some dental problems can't be seen unless the cat is under anesthesia. The pain such problems can cause can be incredible, so terrible, it can cause a cat to stop eating. Even canned food.
Some years ago one of our cats developed a painful problem from a broken tooth. The crown was completely gone, missing. We didn't know when that had happened because nothing showed. The root was still there, buried under the gums. We didn't know that either. When the vet examined her mouth, he didn't see anything out of the ordinary.
We were preparing for a regular dental just to clean the teeth because she was eating less and less and seemed to be in pain when she was eating. Then a few days later she stopped eating completely. So the dental was scheduled immediately. And the root still in her mouth and the painful complications it had caused were discovered.
Just from this experience alone (we've had others as well) I could never, with a clear conscience, talk anybody out of a dental when the person has reason to believe their cat needs one.
The big problem is that pain caused by dental problems requiring treatment doesn't go away. It only gets worse. But I have to say, I don't know anybody, not one person, who would let their cat suffer rather than have their vet do a very necessary dental to take care of whatever must be taken care of to help the poor cat.