It's because our "street legends" are guys that are like Tony Montana, such as Nicky Barnes, Carter Brothers, Freeway Ross, Frank Lucas...they made their money from drug money coming form nothing and being ruthless to get to the stop...that why "Scarface" resonates with them. No question, some rappers haven't lived that life, but they take artistic license creating a false aura ....some rappers have actually lived the life...and no Scarface isn't ruined...let me put this analogy :

Made guys were quoting from "The Godfather" verbatim after it came out and love it, same with "Scarface" with street gangsters...if anything, Scarface is a really iconic film within the hip hop community....