You would write poetry even if no one published you. But you might not revise so carefully.
I made a conscious decision about 5 years ago to stop submitting poems to publishers. It was a combination of things including the time involved, the acceptance:rejection ratio and all the politics and scams involved in even the best publications. But my number one reason for stopping was this: I realized it was changing my writing. At times, I found myself thinking about what a publisher "wanted" as I wrote. In the early days, I would sift through my poems and select things that I thought fit a market (as with those writer types I see in Barnes & Noble drinking coffee and using B&N as a library as they furiously copy addresses from The Writer's Market or The Poets Market).
That's not a healthy way to write.
I mentioned this to 2 poets recently. One said she never gives a thought to whether or not what she's writing "fits" a market. The other person said he figures that people who submit to Poets Online probably have some sense of "market" (if such a foreign concept applies to the site!) if only because the prompt is changing what they write. Hmmmm...
I wonder about that, especially since at least 50% of the poems submitted each month have no connection to the prompt.
I'd be curious to hear from any of you who do submit about whether or not you have a sense of a "what we're looking for" at Poets Online.
If you are doing the submission game, another post by Diane is about on submitting poems to journals via email which certainly beats the snail mail method.