I avoided beginning a discussion on the reasons and ways we have reached this state of affairs, a) because it would really be a departure from Tom's thread which I don't want to hijack, and b) it would take us away from discussing music per se. However you're very right when you mention deconstructionism and relativism which both annihilate (literally) every standard, every value, etc. I'll refrain from name-calling this time, but people like Foucault, Derrida and the like who - grossly put - meshed and confused philosophy with psychology and amateur cognitive science and epistemology are responsible for what's happening at least inside the academic walls.
As far as music is concerned, two quick points: Musicologists, in their unbearable frustration for their lack of serious musical talent, being considered the bottom rung on the musical ladder after analysts, and for their having failed to explain the magic of music to an academic degree, are clutching at straws becoming amateur linguists/semioticians (again taking their cues from current "philosophical" streaks) and amateur sociologists in order to fill pages, make a living, and have something to teach. They corrupt the youth attending their lectures through their perfect inconsequence.
Your example of a professor avoiding a bus reminded me of John Cage, who did admit he didn't take chances when it came to mushrooms...
Sorry Tom, back to you...