Why has apologetics become such a vital function of modern christianity?

People keep asking questions and Christianity would not survive without a plethora of theologians and apologists to come up with answers. I don't know why the inspired work of an all might, all knowing creator of the universe would need apologists at all. A God would surely be able to write in a manner that is clear and easy to understand, that leaves no doubt in the mind of any reader that it is sure brilliance.