Once upon a time, rappers did not talk about what kind of shoes they wore, or their hats, watches, sunglasses, etc. Or the cars they drove, the exotic fur their coat was made out of, etc. At least in the past 10 years, it's become standard to work Louis Vuitton, chinchilla, bla bla bla into their lyrics. I don't recall hearing that in the early '90s, like with MC Hammer or Sir Mix-a-Lot or LL Cool J or whoever. Even the early gangsta rap stuff, up through about 1994, didn't focus on the pursuit of material things -- just rollin' down the street, smokin' indo, sippin' on gin and juice.
So it was sometime during the '90s, no surprise -- that's when the whole culture, whites and blacks alike, started getting materialistic and devoting their lives to petty status contests. But someone who knows rap music better than I do, when did this start?