I guess the question arises: Does the Lord need a Bible to teach us what we need to know, or is he capable of teaching us what we need to know without a Bible? Put another way: How does he deal with people who have never been told of the Bible?
Put another way
Put another way:
if God chose to teach us in a particular way, like with a book, should we really question God's method?
Put another way:
if God created a book, and gave us a book, should we assume we don't need it?
Put another way:
if God could make the entire universe, is he capable of recognizing which people are ready and willing to look at his book... and is he capable of getting a book to those individuals... those who are ready and willing to listen?
And if you want to get really philosophical...
Why would God create the very first man with the complete ability to use LANGUAGE (which requires logic and rational thinking), in order to COMMUNICATE WITH the first man... if God wasn't interested in using LANGUAGE to communicate with man?
Like it or not, God created language, and created us with the ability to use language, so we could communicate, in both directions, with HIM.
God CHOSE to use language to speak to us.
God could have made us to communicate with bursts of squid ink, dolphin clicks, or dog slobber, or honey bee dances, or nothing but psychic powers... but God gave us RATIONAL, LOGICAL, COMPLEX LANGUAGE, complete with ABSTRACT CONCEPTUAL MECHANISMS, in order to COMMUNICATE WITH HIM.