The issue with the True Chaos wasn't something easy to solve, far from it. One of the many species inside the joint front would have already fixed it otherwise.
Some species had ways to partially ignore or directly overcome the True Chaos' annihilating effects, but those feats were limited to exceptional individuals. They also involved relatively unique methods that couldn't be applied to ordinary troops and the main bulk of the joint army.
Those methods couldn't be taught to ordinary warriors, either. After all, they were part of the difference between regular and elite troops.
The only viable and potentially general solution the joint front seemed to have found came from the Great Old One's blood, which had produced some results.
However, the Niqols had been in charge of that research, and they were pretty terrible with technology. Their experimental product was for individuals to use, but Rodney seemed to have extended it to mana-based tech.
