First, while those pinning people down may not be building war chests at normal rates, those hiding in PM will not either. Further it's likely that allied entities have been suggested to stay at elevated military presence reducing their own capabilities to build war chests (to an extent, obviously not nearly so compared to one at war depending on the level of readiness one chooses to abide by).
Second, survivalists have fallen to conquerors time and again. History will repeat itself.
Third, the moral law may indeed push the people to be in line with their emperor, but that too has been shown to be strained time and again, especially in non-top tiers. Morality only comes into play so long as one may be able to actively be involved - to be actively involved this means you're not bill locking yourself indeterminately. Extended bill lock even wares down morality.
Fourth, room to maneuver only exists when the allied entities can be coordinated effectively, timely, and the opponent is fully allocated and cannot cover. That is far from the case.
Fifth, coalition coordination can be extremely effective when done right. It is simply a matter of who is control. This is also true of single alliance coordination.