Final answer:
Oscar Wilde was among the most produced nineteenth-century playwrights until the twentieth century.
Step-by-step explanation:
Until the twentieth century, Oscar Wilde was among the most produced nineteenth-century playwrights. However, it is important to note that while he was popular during his time, he faced a significant decline in the years following his imprisonment.
His works, such as 'The Importance of Being Earnest' and 'An Ideal Husband,' continue to be widely studied and performed today, solidifying his significance in the history of theater.