Bear in mind that God knows the cure for all cancers, but he is not going to tell us just yet.
It's interesting that god writes various books in which god provides direct, undeniable revelation and proof of his existence to select persons (all of whom are now conveniently dead), yet for the overwhelming mass of humanity he is invisible, silent, and gaseous to the touch.
It's also interesting that god manages to pick as his chosen messengers many people who become publicly revealed as liars and charlatans, such as Joseph Smith, Aimee Semple McPheerson, Jim Bakker, Rev. Ted Haggard. (Or, if they are NOT god's chosen messengers, then it is interesting that god never calls a press conference to disavow that these liars and charlatans are his agents.)
It is one thing to believe that an omnipotent being might exist in the cosmos, but if the omnipotent being is omnibenevolent, then you really have wonder about his chosen style and methods of communication. Especially since he designed the way our biological communication and data processing systems all operate...he'd have to know that at least some of us would be skeptical, and he'd have to know that the his techniques of communication and reasoning happen to be the same as those employed by many charlatans and frauds.
One thing god did know: that by commanding us to go to church and sunday school every week, from childhood onward, that it would be possible to build and maintain a mental corral around many people so that thier thinking might never stray into these realms of inquiry.