There is a scene in Round (About?) Midnight, when Wayne Shorter in turn references a scene from the British classic technicolor film Red Shoes.
A composer stole music from a student. The latter writes a letter to the impresario running the show, but than thinks better of it, and attempts to retrieve it before it is opened and read. He ends up getting an audition, and gets hired, eventually replacing the composer. Anyway, at the end of the audition, when he asked for the letter back, he finds out it was already read. The impresario advises him not to worry about it and put it behind him. Also, he leaves him with the thought - It is better to be stolen from, than to have to steal.
But yeah, everybody steals. Some have better taste, are more artful in how they synthesize their influences, and there is a LOT of variance in talent brought to the table in addition to the influences in forging a unique amalgam.
There have been complaints of a racial nature that, while African American musicians have dominated blues, jazz, soul, R & B, funk and certainly held their own in pop, there aren't a lot of black rock artists. Jimi Hendrix of course comes immediately to mind, as an exception to the rule, but after him? Arthur Lee of Love wasn't a major star (perhaps some of that was self-inflicted). I love Funkadelic like Uruk Hai, and while I wouldn't put them up with the Beatles or Pink Floyd, do think they are as much rock and delic as funk, and are great. Living Color wasn't huge.
This has brought ire from some quarters, that original blues artists weren't as palatable as the British white artists that were influenced by them. Maybe it is just a genre thing. I think most are familiar with the concept that jazz music (unless you were Miles Davis, at the top of the pyramid, or a huge seller like Dave Brubeck), is not as high paying a gig as being a rock star. For a LONG time, rock has sold better than jazz (again, there are the exceptions that prove the rule, Kind Of Blue continues to move a lot of units, but maybe not as much as Dark Side Of The Moon). To me that speaks more to taste and popularity, not racism. In other genres, certainly many African American artists have succeeded at the highest level (Michael Jackson owned the Beatles catalog). Miles was very successful, but was still jealous of the popularity and sales of some soul/funk/pop/rock stars, and while he increasingly incorporated elements of the music of James Brown, Sly Stone and Jimi Hendrix into his music in the early to mid '70s, an album like On The Corner, which is for me a masterpiece and one of the best things he ever did, still obviously wasn't hit material. That was his choice. But in his domain, it might of added to his stature as an artist and mystique as an iconoclast.
Hendrix seems like an obvious counter-example that racism may not have been the entire, or even important part of the answer, as he was generally revered and held in awe by virtually all rock demographics (beginning with the musicians themselves, The Beatles, Stones, Who, Clapton, etc.).
* if you think of a pool of influences something like a gene pool, than DIVERSITY and QUANTITY as well as QUALITY of influences come into play. Even before Hamburg, The Beatles seemed to want to differentiate themselves with value add to their music by being voracious listeners and getting rare singles (manager owned a record store or chain) and learning B sides. In Hamburg, playing sometimes 8 hours a night forced them to broaden and diversify their repertoire. Along with playing constantly and sharpening their vocal harmonies and instrumental chops (Malcolm Gladwell in Blink wrote about the 10,000 hour threshold to become a virtuoso in the classical music world, and made this exact connection to the Beatles, I think?), they had a very deep and diverse well spring of inspirations to draw from right before countdown and launch into Beatlmania, which put them at an advantage to virtually all of their peers (that, and having Lennon and McCartney as primary songwriters, Harrison later and Ringo had inimitable charm and musical phrasing/accent, with the latter two perfect complements).
Having fewer or worse influences, would be akin to a genetic backwater, leading to the musical equivalent of in-breeding.
