World War I would be a good comparision of the end of the 14 Year War. There's no evidence that either had any great advantage.
The reason the Terrans suffered so much is in losing Sol, they lost nearly their entire industrial, scientific, and governmental infrastructiron. Everything was concentrated in Sol, from shipyards to the government itself.
The Vasudans likely didn't have that problem. Vasuda Prime was a pretty crappy place to start with, so losing it probably didn't effect the Vasudans nearly as much. Hell, I'd be surprised if the Vasudan government wasn't actually in Vasuda due to it's close proximity to the front lines of the 14 Year War. In any case, the Vasudans likely didn't have their economic core in the system, it was spread out throughout their space, most of which the Shivan's didn't really get to. After the Shivans were gone, the Vausdans had the infrastructure to quickly and easily recover, the Terrans did not.