I think jazz broke down some barriers, but it wasn't until rock and roll that the integration REALLY began.
Jazz was 'accepted' primarily on the coasts and northeast, not the rest of the country.
Remember, the whole reason that Sun Records hired Elvis in the first place was that they wanted a white singer who sounded black. The reason being that black artists could not get played on a lot of radio stations, or play in major venues, in the south.
It wasn't until Elvis that the door in "flyover" country opened for black musicians to get anything near the equal treatment of their white counterparts.
