Gaga is in a much better position than Bieber. Gaga had two hits and sold 700k+ albums in her flop era. She may be struggling, but Artpop proved that she is capable of getting hits with the right material.
Bieber, on the other hand, had to beg iTunes not to report the Journals sales to SoundScan and his Believe movie was a complete flop. The name "Justin Bieber" automatically induces eyerolls. He is hated by everyone who would be his demographic. There are too many obstacles he has to get past to see any kind of success at this point.
Bieber's brand is probably the worst in all the pop scene. It is in a much, much worse state than Gaga's. Gaga is on a similar level of public hate as Nicki, Miley or Chris B, but Bieber has the lowest image of all.
Xtina could easily do at least a theatre tour though. I don't know why she doesn't, probably laziness. If I were her I'd do some "special performances", do like five in the States and five in Europe. She'd probably be able to fill arenas like that.
I met Demi Lovato recently and this is my Meet and Greet story. I met her on October 20th of this year and it was horrific. She was rude, not classy, and lost a long-time Lovatic that day. I walked into the $350 Meet and Greet and said hello. She immediately replied with the word "fat." I shook it off because I thought I misheard her and proceeded with my Meet and Greet. As I approached her and asked her to pose with me for our photo, she looked at me in disgust and disbelief. I continued to speak to her, telling her things like "you saved my life" or "the reason I made it through rehab was because of you" or "if it weren't for you I would be dead right now." Demi looked me straight in the eye and said, "you'll be dead soon enough, fatty." Then she whispered the word "obese" in my ear. I was shocked and scared. I had never felt pain like this in my life. I began to cry hysterically and Demi began to laugh uncontrollably. She asked me, "are you crying? Stop it. Stop it now." Then she flicked me in the vagina. The photographer took our photo and as I turned to leave the Meet and Greet, Demi began speaking to me in whale. It was because of this that I became increasingly overwhelmed and my body collapsed into diabetic shock, for which I was hospitalized for several days. I can't believe this happened. I am saddened and appalled by her behavior. I wish none of this were true but Demi Lovato is a terrible person. I will be contacting TMZ shortly about this encounter with the white devil.