Who do You think worked hardest to get at the top in show business ?
Choosing from the favorites here.
In my opinion, Madonna.

She basically became GLOBAL without the Internet. She became a global phenomenon when most people in the world had no access to the Internet or social media. She reached the top and became the most successful female musician even based solely on hard work from her part (performing and hard promo). She moved to New York and lived Ina. Rat infested apartment, got raped, etc and still came out victorious. 32 years later she's still as famous as she's always been.
I also have to mention Beyonce.
The fact that 15 something years later after her debut she's still at the top of the game when most of the stars that debuted with her have burnt out or faded away. She works hard and is a good business woman, like Madonna.
Honorable mention to J.Lo

Another woman who built an empire from the ground. Music, perfumes, fashion, entrepreneur etc.