Was really just kidding around, but if we look at MMA accomplishments, they're already comparable, and Brock is done.
I can see Rousey defending a bunch of times, and while I have no idea if her per-card buys will out-perform Brock's, I have little doubt that she will be one of the top total $$ draws in a fairly short timeframe.
Yup I know, I got the hint with the stick poking animation lol. Well Brock might be the biggest star in UFC history, but I'm sure Rousey will end up being a better fighter for the division she's in (if she's not already).
There really doesn't seem to be the #2 current draw behind GSP. It seems like Silva, and Bones are right around it (Rashad & Rampage were, but not really anymore). If she keeps winning, it could easily be Rousey.