There were several reasons that the term and concept only came into use so late. First, the Enlightenment really celebrated individual achievement and the capacity of reason and progress, all ideas that led to the celebration of individual musicians for their mastery of the technique of the instrument. Second, the instruments themselves had to be developed enough that people could be impressed by the technique of the performer. Early harpsichords and even pianofortes, for example, were universally quiet, had little range, and had clumsy, inconsistent mechanisms. It took better materials, machines, and techniques to make better instruments. The 1800s began a fashion for truly showy pieces; violinists like Paganini (who wrote a series of 24 extremely difficult caprices, setting off a tradition of virtuosos writing 24 studies, one in each key) and later a series of pianists like Liszt, whose tours set of "Lisztomania"--that's actually what they called it--toured Europe and made reputations first as showy performers and then as refined composers. Here is Liszt's version of the last of Paganini's Caprices (the same one that Rachmaninoff would later use for his famous Rhapsody); it is a serious competitor for the most virtuosic piece ever written for piano:
The piece is the last of Liszt's Grandes Etudes de Paganini, all based on Paganini's Caprices.
The epitome of self-indulgent virtuosity, well beyond the Enlightenment ideal of the restrained but well-trained performer, is Balakirev's Islamey. Mily Balakirev was the leader of the "Mighty Handful" of Russian nationalist composers; after a trip to the Caucasus, he decided to write an orientalist piece that would also happen to be absurdly, showily difficult. Here is a recording of it:
This grew out of a demand for ever more difficult pieces; it was and remains popular simply as a sort of rite of passage for pianists to show that they have completely mastered the piano technique--as I said, far from the enlightenment ideal of the performer, but still an outgrowth of the same idea.