Hmm. How is this right enforced? Is is a statute (I think that's when a specific law is legislated, written down in kind of a rule book), or is it case law (I've been told this comes down through appeals), or tradition? You speak with confidence about "rights"--I don't understand what sort of right you mean.
Now, just as a citizen with only sense for my tool, it would seem very dangerous to force an insurance company to function the way you suggest we have a "right" to expect. If an insurance company cannot quarrel with a demand for payment, it will not be in business very long. I'd like to understand how this works?
Since then, those duties of good faith had been statutorily codified, and the overall result has been that insurers were less free to arbitrarily deny claims or to throw up spurious policy defenses in order to roll the dice.
Here is how it works....an insurance company can not deny a claim if it does not conduct a reasonable investigation or if does not have a reasonable basis for denial.
For instance, lets say you, the insured, has $50K in coverage. You get into a car accident (your fault) and kill a family of four. Obviously, their damages are in excess of $50k, and the plaintiff's attorney demands your insurance limits. Your insurer can not, in good faith, deny this claim, particularly since the damages are likely to be in excess of your limits and, therefore, involve your personal assets.
Surprisingly, some insurance companies have internal documents that, um, "suggest" that claims should be delayed or low-balled.
Finally, I would suggest that you learn how an insurance company makes money before you go spouting off....