Keep in mind - determinining who was winning a 14 year long war 32 years before FS2 can't really be any indicator of the technology levels of the two sides in the FS2 Time Era. Look at the world 32 years ago - Not my area of historical expertise but I think Russia was in a lot different a situation than it is now, same as Japan, China and a lot of other nations. 3 decades is plenty of time for certain areas of technology to advance more than others.
Really though, it makes sense that the Vasudans are the better species technologically. As has been said, Vasuda was probably fairly resource short, and, unlike earth, actually fairly hostile to life (meaning a fair number of Vasudans would have left as soon as it became possible, meaning their core was actually probably several planets, probably spread over several systems. The Terrans, on the other hand, probably had a lot of research and a massive population base on Earth and in Sol colonies. When they lost them, they probably lost a hell of a lot more than the Vasudans did, plus of course, we know the Vasudans made a quicker recovery, and they were solidified almost immediately post Great War, unlike the Terrans who splintered. Everything after the Great war(well, except the NTF) was going Vasuda's way.