Sure, the typical image of an idol is a solid object carved from stone, or clay, or even wood. It might be painted, and it might be adorned with gold or gemstones. In our mind's eye we picture uneducated pagans bowing down, making their petitions to this object. However, an idol isn't necessarily a solid object. An idol can literally be anything for which you live, or which gives your life meaning, or which would cause you serious depression if you could not have it. With that broader description, an idol could be almost anything. For instance, a certain type of physical body. The goal of being considered intelligent or helpful. Even success at getting published.
"But wait!" you object. "I want to get published for good reasons. My manuscripts glorify God. They contain important messages people need."
However, explanations make no difference. We can rationalize our "need" for any idol, including weight loss, education, productivity, and even getting published with with good, God-glorifying material.
I will not suggest for one second that all writers over-emphasize getting published and idolize that goal. I don't believe that at all. Yet, when I see the deep pools of depression that some sink into when they can't reach that goal--or can't re-acquire it after some initial success--I can't help but wonder whether they are elevating the goal to too-lofty a pedestal in their lives? Rejection slips serve to keep me humble and to remind me that--no matter how many manuscripts I've had published--I should never live for getting published.
Dear friend, getting published will not give your life meaning. It will not affirm your reason for existence. It will not grant you new respectability. It will not add a glistening halo above your head. It won't make you special in any way. So, if you knew right now that you would never be published (or never again), would you slump into depression? If so, perhaps this publishing goal has grown into an idol in your life. Perform a heart check. Better yet, ask God to examine your heart. If your goal of writing for God has grown even larger than your love for God Himself, that would be a vital lesson to learn!
May the Lord bless you!