perhapss
Headphoneus Supremus
There seem to be two approaches to programming modern works alongside classics: stick the modern work on the first part of the program so everyone has to sit through it (or risks coming late to the second part) or stick it at the end so people can leave early. I go to piano recitals, where the repertoire is even more standardized, so the problem doesn't come up.
My old man really enjoys modernism, which he calls "the music of my time." I like to say that I too enjoy the music of my time: the Baroque.
I generally avoid major American orchestras when this occurs as it kills my spirit.
About a decade ago I saw James Levine program Elliott Carter and Mozart together in Boston and the sea of restless,
muttering, white haired old women and coughing, shifting, elderly men was enough to ruin the whole night.
Nothing against the elderly, I too am not young but...
And this kind of thing is not limited to mixed genre concerts.It's commonplace anytime an American orchestra plays modern music.
I've seen it often.
For example I saw Boulez conducting in the mid 1990's in Cleveland.
This concert was specifically billed as a program of 20th music consisting of Stravinsky, Varese and Berg.
In the middle of a quiet section of Berg's 3 pieces for orchestra a party of 5 or 6 elderly couples insisted on leaving the concert in a noisy, talkative fashion.
They looked as if they had been personally assaulted.