How did "lean" and rap become so interconnected

Hip-hop created many trends that went mainstream. Let's just focus on vernacular alone for a split second. Think about how commonplace words like "yo," "dope," and "word" are in the American lexicon. In addition to copious verbiage, one could easily correlate the rise of streetwear to rap's cultural omnipresence. Hell, we haven't even gotten into how absurdly important butts have become on social media and in real life. Rap has profoundly impacted how American culture functions in modernity by putting often overlooked aspects of our society directly in the public eye.

However, not everything rap has lent its spotlight to has been a boon to society. One needs to look no further than the rise of "lean" or "syrup" to elucidate the point. In the video linked above, you can check out a brilliant essay explaining how lean and hip-hop have developed one of the most toxic relationships in music history.