We are not born with faith. This is something that is acquired over time. The dictionary definition of faith is "complete trust or confidence in someone or something." When we are young we base our faith on our parents and/or teachers. Then as we grow older and acquire more knowledge we realise that our parents and teachers were not always right. So if someone wants to have faith, we have to seek it from a higher authority. And for it to be unshakeable, it has to be from a source other than human.
It should not surprise us then that we are bombarded by propaganda from Satan and his demons, which has caused millions to lose their faith in God.