You're suffering for 2 reasons:
1. Because she doesn't need the money, and even if she does need more she has acting options which is better than the music industry. Girls like Lalah Hathaway, Fantasia, and Mya keep their fans fed by releasing new music and touring cause they have to. For the most part music was their only avenue to make money and they never had a slew of major brand deals.
2. The passion is not there. She has nothing to prove. She's an amazing vocalist but she was never an artist outside of the studio. Brandy's vocal arrangements is where her artistry ends. She doesn't care about visuals and live shows like a Gaga, Janelle Monae etc. She was a teenager who had dreams of being a megastar like Whitney Houston, mission accomplished. She was a teen pop star, we all just lucked out by actually being able to witness her mature into a superb influential vocalist. Brandy has a love for music and recording but it ends in the studio where she let's it all out. She's not that artist that's dying inside if her precious art isn't being released to the public or if she doesn't hit the stage.
Bonus: She's also not thirsty or desperate for fame and willing to do anything just to stay relevant. Ciara and Kelly Rowland are clear examples of that. Alternatively, look at how someone like Ashanti just goes out and makes her show money then goes right back to being on vacation despite being commercially viable.