1000 people in a city get sick and are told they have terminal cancer. They all go to a hospital for treatment and they all pray to G-d to be healed. The ones who are rich get the best medical care and are able to afford special cancer drugs that cost $100,000 a year. Those who do not have insurance get lesser medical care. Those who get well thanks G-d for being healed, those who don't accept it as G-d's will.
Now which side do you really want to be on- without insurance and prayer only? - or on the side with AAA insurance and the money to pay for experimental drugs/treatment? The few people who seem to have miraculous faith healings tell their story for the next 20 years. The other 80% who didn't get healed by G-d ,die and we never get to hear their story. Religion is not in the business of keeping talley of failures when it comes to prayer.