I put off writing the first Left Behind book for a year because I got invited to assist Billy Graham in his memoirs, and had we known what we were putting off for a year, we might not have put it off.
I fear it's because religion is man's attempt to reach God, and when he feels he has succeeded, he cannot abide anyone else's claim to have done the same.
I've written enough books with real celebrities, such as Walter Payton and Hank Aaron and Billy Graham, to know that fame looks good only to people who don't have it.