For how crazy they sound, FWC might be the ones who have thought about everything most. They actively research time travel and alternate time lines, and discovered that earth has a chance only in a few of them - and in all of them - all out war is inevitable. Considering the Vex are our greatest enemy, and the greatest threat they pose to us is the fact that they've established themselves as a fact of the universe in almost every time line, FWC just might have it right.