I think the level of ignorance in society in general in the USA is
increasing, so it would not be surprisising to see it increasing in the
audience of classical music. And at least in the US, the information
given over classical music stations, while sometimes quite good, would
not replace a music theory class.
As a fairly unsophisticated listener, I can't really comment on the level
of ignorance today as compared with previous times. However, this "boomer
baby" is confident that over his lifetime, audiences have become less
respectful of the music, the musicians, and fellow audience members, and I
find it distressing. When I heard Ormandy's Philadelphia Orchestra in the
1960's, I am almost certain audiences did not fidget to the extent they do
in Washington DC today and applause between movements was not nearly so
common as today. Many on this list don't need to be told that Kurt Mazur
walked off the stage a couple of years back in disgust at the audience's
lack of attention.