Needless to say, anybody who can stumble through a C-major scale knows that Art Tatum always gave his audiences 10 times their money's worth.
I feel quite confident that audiences on both sides of the Atlantic are growing 'dumber,' if what you really mean to say is 'less culturally literate.'
Tom Stoppard, the English-speaking world's brainiest playwright, thinks that British audiences have grown too dumb to understand his plays.