For the first question, it was difficult to the nature of American Literature. However, it has never diminished or gone. Many writers have been finding ways to improve and find another way or style of writing various pieces, i.e., free verse.
For the second question, the use of literature has been evident up to this date. It may have been reinvented, but it was never gone. Books for American Literature had been made available to many wide readers and thus, continue to exist.