Final answer:
Gangsta rap, with G-funk being a notable sub-genre, was the most profitable sub-style of hip-hop by the mid-90s, largely due to its wide appeal and commercial success, despite criticisms.
Step-by-step explanation:
The sub-style of hip-hop that was most profitable by the mid-90s was gangsta rap. By this time, gangsta rap had surged in popularity and commercial success. Artists like Dr. Dre, who pioneered the G-funk sound, a sub-genre of gangsta rap, were dominating the charts with albums such as 'The Chronic'. Gangsta rap's explicit lyrics and portrayal of inner-city life resonated with a wide audience, contributing to its financial success. Despite criticism for often perpetuating stereotypes and misogyny, gangsta rap's impact was profound, influencing both the direction of hip-hop music and the broader cultural discourse around race and class in America. It outpaced other sub-genres like conscious rap, which focused on social issues, and East Coast hip-hop, which was known for its complex lyricism and boom-bap sound but didn't achieve the same level of mainstream appeal.