historically this has always been true of rappers in general. it's always been a manlet dominated field. the 6'6" slim thugs, 6'5" 2 chainz/tity boi, 6'3" snoop dogs, 6'2" lil flip, 6'1" dr dres, and >6'3" No Limit boys (Master P and his brothers) were the outliers
when you grow up in the 'hood you believe there are two non-illegal routes to success:
1) rapper
2) athletics
-the bigger guys spend most of their time trying to become athletes (even Master P and his bros tried this route)
-the shorter guys transition into trying their luck at rapping much sooner