Over 90% of Beyonce's peers that came out in 1997 with her until now still can't pull Beyonce tour numbers though. Ask Brandy, Ashanti, Monica, Usher, Avril, Linkin Park, Evanescence, 50 Cent, etc. Hell, ask Britney Spears and Christina Aguilera.
But I thought that Circus tour outgross I Am tour?
If time in the industry affects your touring abilities then please explain how Gaga's first tour as a headliner grossed $227,000,000 in the third year of her career.
It's pretty clear Katy doesn't have the worldwide presence Beyoncé has.
That's like saying why isn't everyone selling 20m+ albums since Adele did it. Gaga is not the standard in the touring world, she's the exception.
I won't even bother.