This is one of those weird debates, acrimonious and nasty, in which I fundamentally disagree with both sides. Traditionalist Heather MacDonald wrote this essay, which ticked off modernist Greg Sandow. (Here is her reply.)
Her idea is basically this: Classical music is flourishing today as never before. The standard of performance is higher, there are more performers, there are more works available, audiences are more sophisticated, than ever before. You even have instant access, she points out, to beautiful performances such as the one I've embedded above. Classical music is in a new golden age.
There is a huge gulf between the way this person thinks about the arts and the way I do. Look at it this way. The reasons she gives for thinking the music is flourishing are: a) the performers of the music, b) the conduits by which the music is communicated to the audience, and c) the audience that listens to the music. What is missing from this list, class? Anybody? Anybody?
That's right! The music!
Here is an analogous argument: Dodo birds are flourishing today. More museums have dodo bird exhibits than ever before. Their quality is higher than ever. You can even see stuffed dead dodo birds on the internet! For free! So don't give me that stuff about how the golden age of dodo birds is dead and gone, pal. You're full of crap.
Okay, that's a little silly. Here is a closer analogy. Poetry today is flourishing. There are more volumes of old poems written by dead people than ever before. Previously unknown old poems are discovered and published every day. And they are embalmed in such beautiful editions! You can even read old poems by dead white guys on the internet!
I have been told that the most recent piece of classical music to become an established part of the standard repertoire is Strauss' exquisite Four Last Songs, which was composed in 1948. If the last poem with that sort of status were that old, no one would be giving an argument analogous to MacDonald's that poetry is flourishing.
I guess the reason it is possible for an intelligent person to give an argument like MacDonald's is that she doesn't think of classical music as an art like poetry or painting. What she means by "classical music" is something like the world of people who collect antiques, old coins, or classic cars. It so happens that the world of classic car collecting is flourishing. There are several shows every year in my area. More classic cars are being restored and displayed every year. It's really cool. But the giant automobile with tail fins is not flourishing. It is as dead as the dodo.
And so, it breaks my heart to say, is classical music.
BTW, here is a more professional performance of "Cum Dederit Dilectis" than the one to which she directs us: