It matters what you mean by destroyed. If you mean popularity, I’d say if anything there seems to be an uptick in that due to orchestras finally coming to their senses and playing more pop music like movie scores. If you mean the craft of making new classical/orchestral music, that was ruined in the middle of the 20th century with the advent of atonal music (which also destroyed jazz as well). I’m afraid we’ll have lost at least 2 generations to atonal music due to professors in colleges over emphasizing it currently. A bigger issue, tbh, is the way Hans Zimmer has destroyed movie music, which has enjoyed 80 years of success.
So if you mean popularity, then all is as well as could be given classical will never become “pop” again. If you mean the music being written today sucks, then blame 20th century composers for a shift to atonality which was never going to be popular and drove the most talented composers away.
