While I know this survey is biased, it’s people who watch Brulosophy content and answer surveys, but my own experience backs this up: https://brulosophy.com/2024/05/27/2024-general-homebrewer-survey-results/
My personal experience mirrors that as well. Everyone in my homebrew group is that. Everyone in surrounding groups (as seen in pictures of state-wide gatherings) is that. 95% of the people I see in homebrew shops are that.
Why?
The middle class part makes sense. You have to be someone who both owns their own property and also has significant leisure time.