Hello Cozyk,
I think Fred has summed up things pretty well when he says that God still inspires people. I also think Fred's explanation of tradition is pretty close to the mark.
We need to appreciate that the bible was written in a completely different time to our own. Now this may sound a bit terse but is is very significant.
Today we live in a very complex society with competing theories of knowledge. To put this another way, we live in a society which is as complex as it is critical.
Anyone who comes forward and claims that they can legitimately add to the Bible would be treated with great scepticism, and rightly so. After all, there have been a lot of false profits in modern times.
The sad thing is that everyone is rejected. This is regardless of whether they are genuine or not.
I hope this goes someway to answering your question. I might add that it is a very good question, but very difficult to answer in a few lines.