They make you jump through hoops, they may require you to attempt other treatments, but if you qualify (and by that, I mean under generally accepted medical guidelines, and with
FDA approval), ultimately, you will prevail.
This only got easier under HCR.
Do you recall any new AIDS drugs getting FDA approval, but being denied, en masse, by insurance companies? It just does not happen.
And for the record, there is PLENTY wrong with insurance companies denying coverage.