Richard Taruskin

"Ever since opera opened its doors to a paying public - a public that had to be lured - it has been a prima-donna circus with a lively transsexual sideshow, associated from the very beginning with the carnival season and its roaring tourist trade. Uncanny, nature-defying vocalism easily compensated for the courtly accoutrements - the sumptuous sets, the intricate choruses and ballets, the rich orchestra - that the early commercial opera theaters could not afford. Never mind the noble union of all the arts: what the great Russian basso Fyodor Chaliapin called 'educated screaming' is the only bait that public opera ever really needed, and its attraction has never waned."

-discussing the divergence of commercial opera from the court spectacles (which considered virtuosity in music tawdry) of Monteverdi's era. Oxford History of Western Music, Vol. 2 . pg. 16 

Basically, this is my new favorite quote about opera.