The arts in general in the US are dead. Nope.
Many schools are getting threatened to have to cut the arts programs because "it is not popular". I remember hearing that in the 80s. Schools still have arts programs and high schools for performing arts are still in cities all over the country.
At my school, all it is about is sports. The drama department put on a preview of How To Succeed for all the students, and the students were talking and yelling words like "SLUT!" out during the show. I agree that the behavior of kids has declined somewhat (when does it not?), which has always been a complaint from generation to generation, but I'm not convinced the behavior of the kids at your school is the barometer for the deterioration of the arts in the US. I remember when a group of high school kids got kicked out of a movie theatre in Houston for laughing and making derogatory comments during Schindler's List. Films are still being made. It sounds more like the students were either bored or under little-to-no supervision. They behaved the same way many audiences did during operas, plays and ballets for centuries in Europe. I think that is more of a sign of the deterioration of morals and discipline, not that the arts specifically are dying.
Broadway, Off-Broadway, regional theatre, community theatre, school theatre, music, opera, ballet, and all forms of visual arts are still alive and well across the United States. They are evolving as they always have over the centuries.
I don't know which is more detrimental to the arts: people who don't appreciate what they see or "artists" who claim art is dead when things don't go their way. Even in periods of political and social strife including major bans of art and expression, art continued to live underground until it could once again resurface free from the constraints of dictatorial rule. To think art is dead in the US now is to laugh in the face of artists who truly struggled and/or died for their art in times when art was truly under attack.
"What can you expect from a bunch of seitan worshippers?" - Reginald Tresilian