How did the most visible poet in the US become nearly forgotten?

"Early in 1914, having heard a young and unknown poet perform in Chicago, W. B. Yeats approached him and asked, 'What are we going to do to restore the primitive singing of poetry?' That young poet was Vachel Lindsay," writes Terry Hummer, a professor of English at ASU, who was a guest columnist for Robert Pinsky's Classic Poems section of Slate.com.

Hummer continues: "Yeats’ recognition of something unusual in the style of the performance was the beginning of a strange episode in American literary history.

"Even dedicated readers of poetry in our own time can be divided into two groups: those who know Vachel Lindsay and his work, and those who don’t. When I was in my teens and 20s, the first group was by far the larger; now the latter is, and the difference in magnitude between them seems to grow exponentially with every passing year."