At first glance, I thought this thread was a wind-up, but after reading through, I find myself unsure who exactly "middle class people" ARE, and thinking there might be a different set of criterion used in the UK than the US where I live.

I've always thought that middle class meant middle income, and some of them would be "working class" as in unions, trades. What it feels like is that the current economic and social trend is shrinking the middle, with more sliding toward the poverty end of the scale, and a few gathering up a disportionate percent of available wealth. This economic trend seems to correlate with a decline in the numbers of those who participate in making music. Mike of Northumbria pointed out leisure time and education components as in the decline in numbers participating. Here, the arts in education are treated more and more as unnecessary luxuries, while the STEM * programs get the attention and funds. Without education that includes participation in performance in the arts, it is no wonder fewer participate.

Back when I thought I was middle class, I got started playing music and singing because it spoke to me of heritage, history, and a feeling that I could participate on the continuity of this significant part of the cultural heritage I valued. Now that I'm tipping over into poverty, I still value all that and cherish the community/social side even more.
Why I play - call it a sense of belonging where star status is not required to participate. Popular culture norms seem to be antagonistic to amateurs. Wish more of us WERE middle class and making music.

Joanne in Cleveland

*STEM= science, technology, engineering, math