You don't see why Madonna, Bey and Rih would promote Jay Z's business ?
You don't see why Gaga would NOT promote Jay Z's business ?
I can't help u, actually I can, but I won't.
At you thinking Lady Gaga's power has declined only because of her firing her manager and having no marketing schedule for her album after the 2nd single was released
Lady Gaga's networth keeps INCREASING, her connections keep increasing.... she is more powerful NOW than she was in 2012, 2013 or 2014 simply because she survived 1 underperformance and every media outlet talking **** about her and have a lot more connections now especially because of C2C the Oscars etc.
She is having a LEAD role in American Horror Story..... you have NO clue what all these connections are going to do for Gaga in the future Just wait and see.
Did I mention that she is considered for Gypsy's main role ?
I can't help u, actually I can, but I won't. 
You probably just wanted to see that. 
