It should be noted that not all claims denials mean people aren't getting the support they need.
For example I had an insurance company not want to pay for a particular prescription drug my doctor prescribed. They were happy to pay for treating me, but they wanted it be done with some other drug.
They actually had a medical reason for this. The drug I had been prescribed had recently been found to have a risk of bladder cancer. There were other drugs just as effective but that did not have that risk and so they had removed it from their formulary.
In this case I wanted the first drug because I had used it before and knew that it worked well for me and that I didn't get any of the numerous annoying side effects that it and the alternatives could all have, and I had good reason to believe that I'd only need to be back on it for a month or two and then would be permanently done with it.
I concluded that the risk of bladder cancer from a couple months of the drug were negligible and preferable to dealing with drugs I'd never had before.
My doctor probably could have convinced them to go ahead and approve a one month subscription with the possibility of one refill, but I realized the drug was one of the ones that Walmart had on their $4 drug list and so had my doctor send the prescription there and I bought it for the cash price.
BTW, that $4 cash price at Walmart was cheaper than what I would have paid if my doctor had convinced the insurance to cover it and I filled the prescription at my regular pharmacy.