<...> Good win but here's a question : when you're winning matches in rapid fashion what happens when you suddenly find yourself in the later rounds?
Rousey will cross that bridge when she gets to it. (Or, IF she gets to it?)
Let's not jump ahead of ourselves here. Before we discuss what will happen in "later rounds" let's first see if somebody finds a way to survive the 1st minute, let alone 1st round. Only way anyone can take Rousey to the "later rounds" is to find a way to keep the fight standing, because once the fight goes to the ground, the arm-bar is just a formality (as is becoming more and more evident).
Unfortunately (for majority of Rousey's potential opponents), skill-set required to keep the fight standing against an elite level judoka is not something that can be acquired in couple of years training (as strikers like Julia Budd are attempting to do). Other then another high level judoka only an elite wrestling athlete may have a suitable skill-set to accomplish that. (An olympic medalist in wrestling like Sarah McMann would seem to fit the bill here.)
It can also be argued that even though her wrestling ability may not be at elite level, a freakish physical specimen such as Cyborg Santos may also be successful in keeping a fight with Rousey standing.