1. Beyonce was never the "leading lady" in pop music on a worldwide level, not overall or not during a specific period of time. During the DIL era, Dido was selling more albums and Britney's singles had more WW success. B'Day era she was overshadowed by Shakira and Nelly Furtado and Rihanna. IASF era she was overshadowed by Lady Gaga and Taylor Swift. 4 era....well...
2. Rihanna on the other hand dominated during late 2007/early 2008 and arguably in 2010 again, she continues to have massive worldwide hits and has more successful singles and albums than Beyonce. She has already surpassed her in success and fame. Rihanna is the bigger star and artist, hence her not needing the Superbowl + massive promotional tie-in to restart her career.
