There are plenty of exported musical genres where the connection to the culture of origin was completely sundered. It only takes a few decades for that. Finnish

There are plenty of exported musical genres where the connection to the culture of origin was completely sundered. It only takes a few decades for that. Finnish tango has no connection to Argentina. Irish traditional music plays a lot of mazurkas (a traditional Polish form that came over) with no acknowledgement of or even awareness of Poland. Only natural the same would happen to hip-hop. Also, because hip-hop requires as a minimum nothing more than a source of a beat and the ability to do intricate wordplay, and is arguably the most accessible of genres, it has found root in impoverished communities worldwide. People in those communities might not have the relatively privileged background that would allow them to explore the history of the genre and the original culture in the USA that it came out of.