There's always been what I would call the William Carlos Williams strain, in which poems of simplicity and clarity are valued by a different community. I was talking to Galway Kinnell one day, and he said that there was an audience for poetry up until about 1920 and then, from that point on, the poets and the critics drifted.
Every poet gets to choose what kind of community he or she serves with the poems, and it's true that there is a community for very difficult, challenging poetry. It's a community that's established itself over the last 80 years, that was originally, in effect, really started by T. S. Eliot and Ezra Pound. They believed that poetry ought to contain learning, that it ought to rise upon all the learning that went before.