Well, obviously Revan is going to win the prolonged battle. But Traya, wise as she is, knows this and would do what she can to defeat Revan's forces with the people she has. Traya can mobilize assassins to infiltrate Revan's forces and wear them down. The threat of infiltration impacts an army greater than the actual infiltration. All that needs to be there is the possibility for Traya's assassins to be lurking and the Republic soldiers will slowly go mad.
Revan would win a prolonged war, but that doesn't mean that it will happen. If Revan tried to wait her out, he would see his troops slowly fall apart. Traya would turn Revan's strategy against him.
You see, you kinda argued against yourself a little bit there.
Point: We agree that Revan would win the prolonged war. I'll work with that.
Let's look at the possiblities at Traya's options ('cause options win wars):
1. She can sit at Malachor V and attempt to erode Revan's army slowly with. But as I've already explained, Revan's logistics are too good to be eroded like so.
2. She can engage Revan in a battle. This way, she loses. Period.
note: Traya's assassins are only gonna help (significantly) in a prolonged war. In a prolonged war, Revan will adapt to the assassins techniques, meaning that the assassin's usefulness is limited.
Now for Revan's options:
1. Attack Traya at Malachor V. If he devouted many of his men to such a battle, then he loses the war. But he know's his master too well for this to happen. What would likely happen here is that he'd send a small portion of his force to Malachor, they'd be destroyed, and Revan would learn his lesson. He wouldn't make the same mistake twice.
2. Revan attempts to get Traya into an open battle. IF it worked, he'd win the war.
3. Revan sits out the war, starving Traya out. This results in a victory for Revan.
In the end: Traya just doesn't have as many options. The only
way she wins is by Revan making a BIG mistake, which isn't likely.
I have now made up my mind: it's Revan's battle to lose.