You specifically cited the low number of black musicians in classical orchestras so lets start there; pro musicians and their options.
Classical performance don't make money. I know lots of professional musicians (I make music videos for them, do publicity, sing backing vocals). None of them are in love with playing covers or being in tribute bands (well one is but he owns two tribute bands...)
Think of it this way, for an artist, classical music performances are the equivalent of being in a tribute band. IOW you have to play it exactly the way the audience thinks it should be, no improv, no changing the tempo, the style the dynamics, etc. No having fun or expressing yourself. Worse, IMHO, is you get a patronizing pat on the head for allegedly being culturally superior but you make less money than musicians who play in modern tribute bands. Bands that perform note-for-note tributes to Pink Floyd, The Who, Zeppelin, and Dave Matthews charge $5000 a show and only have to split that among 4 to 7 members. Playing in an orchestra can require owning expensive and delicate instruments yet pay as low as $100 a gig. With no comp for transportation, lodging or meals, you can wind up losing money. If your instrument is lost, stolen or broken, you can lose a lot of money.
My impression is that efforts to recruit more black musicians into classical orchestras has failed because no one wants to be a token; no one wants to be patronized. Here is one experience:
Musician A is a fully-tenured orchestral musician, who shared, I wouldnt go into a major orchestra as a POC with the idea that I will be socially comfortable there right away. But they also offered some validation and encouragement: Dont be too disillusioned if you get there and dont feel instantly comfortable.
https://icareifyoulisten.com/2024/04/its-not-just-an-access-problem/
That's three big reasons why black musicians don't want to be in classical orchestras -- very limited artistic expression, low pay and a snobby hypercompetitive work environment that is likely to tokenize them.
Despite all that, this exists: