Angela Davis has a lecture in which she discusses how music is more integral to everyday life and activities , such as labor, in traditional Africa than in traditional Europe.
I'd say classical jazz, as you describe it below, was integral to partying and recreating away from work - urban folk/workers' music; speakeasy, juke joint music. The key issue is the level and quality of audience activity and participation.
From: Carrol Cox
Could "classical[a] music" be defined as dance music turned chamber/concert music? My grasp of music history is perfunctory, but I believe that the traditions out of which first baroque and then "classical [b]" (=pre-beethoven) music developed were all dance traditions. And that concert music evolved from chamber music.
If so, then what Justin defines as a loss is more like the shift from Dowland to Handel????
_Different_ but neither better nor worse.
Carrol
P.S. Problem with terminology above, since "classical" has a least three separate senses, not easily disentangled. The "Jazz Classics" would not be "classical" in either sence a or sense b above, but in the popular sense of "classical," the best, the original. Someone else can try to untangle this if they care.