Clinton was my high school years Graduated under Bush, my sister was under Bush for high school and graduated under Obama. I think during the Bush years was when they significantly started to cut because of what I heard from some of my sisters friends who were in Band and had to raise most of the funds to go to the State Capitol for a competition on their own.
Two guesses: one is that they are hoping it will steer them into a tech field where they will make money for a larger corporate office.
Two is that they figure that with the net kids can teach themselves, or outsource to groups that you have to pay for to cover that. Think 4H but being paid for your kid to go to a art museum.
What doesn't help is that parents dont think about taking kids to culture places. I don't mean the ones that can't due to work, I mean the ones that have the money but won't.
Example: my sister in middle school had me chaperon her class to the art institute of Chicago. Her science teacher's mom was another. The mom came over to me and asked me how I, who was just a freshman in college, knew how to get around the Art institute without a map. I told her it was because my parents had been taking me there since I was 4. I asked her if she ever took her daughter, she responded, no, that she didnt think a girl of 4 would apparently get art and her daughter first went there on a field trip when she was in middle school so 12 or 13. It just blew my damn mind.