Interesting! It was the same when I went to elementary school band lessons in the early 70s. They made me take sax because they had enough drummers. I finally pestered my parents enough to get me private lessons. I went in, auditioned, and became drum captain my first year. Because I WANTED it. lolI've had 2 kids go through the elementary school music program and a 3rd who will start next year. Every year when it comes time to sign up for an instrument, there is a need for a lottery for percussion because there are too many kids who want to play. From my perspective, there is no shortage of up and coming percussionists.
I am on Long Island just outside of NYC, the epicenter of middle class families in detached single family homes. I am not a sociologist, but if you believe that social class is a factor, well maybe it is.