Here's a list of
Symphony Orchestras in the U.S. I couldn't find financials for them though.
But
here's a recent article about the decline in average salaries for working classical musicians in the US. Sad news but still... 80K - 150K annually at the top and 10K - 49K for the average musician.
Considering that most working musicians don't earn even 10K annually, I consider this good evidence for the relevance of classical music.