Odds of Getting In
Becoming a full-fledged, honest-to-goodness successful poet—someone whose main profession and source of income is writing poetry—is extremely difficult. In case we haven't driven that idea home by now. In order to get to that point, you'll have to write thousands of poems, submit to hundreds of literary magazines, and publish dozens of collections. Billy Collins has published 13 collections to date; Nikki Giovanni has put out 18 and written several children's books; Mary Oliver has written no less than 28 poetry collections.
Of course, if all you want to do is get published, your goal will be a bit easier to achieve, although it's still no cakewalk. Many publishers will only agree to put out your collection if you've been published before, either in a prominent literary magazine or through a first book prize. Even once you've been published, that doesn't necessarily mean that you've made it. There are countless published poets who remain completely unknown and uncelebrated throughout their lives and careers.
As we've discussed already, though, you're clearly not in this for fame or fortune, so we suggest plugging away, writing and submitting as much and as often as you can, and being published by anyone who will have you.