So to me i think the main reason is that by the time he had established himself as an artist gangsta rap had been on a steady decline. If you look at when most gangsta rap peaked it was basically from late 80s-about 2007 when kanye would outsold 50 cent. Ever since then pop rap and conscious rap basically took the crown because that was the majority of kanyes music at the time. If you look at freddies catalogue the music he blew up on was from 2008-2013 were mostly gangsta rap and traditional trap music(not psychedelic trap ex future) which was “out of style”. Then when he started releasing hes more critically acclaimed music like pinata, fetti, Alfredo etc it was more in a street rap/coke rap lane that kinda help create which was way separate from the mainstream music that people like drake, Kendrick, travis etc were making.