Obsolescence
At the peak of its development, the harpsichord lost favor to the piano. The piano quickly evolved away from its harpsichord-like origins, and the accumulated traditional knowledge of harpsichord builders gradually dissipated. The old harpsichords were not valued, often destroyed (for example, they were used in the Paris Conservatory for firewood), and the instrument was something of a ghost for the duration of the 19th century. One exception is the continued use for recitative music in opera well into the 19th century, the fact that it did not completely disappear from the public eye played a role in revival efforts that began in the mid-19th century. However, by the late 19th century, despite revival efforts, its use even in the recitative style began to disappear.
Read more about this topic: History Of The Harpsichord