I really disagree here. The only option they didn't have was to attack Luria (which, even that, I think was time-limited because I hate diplomatic limitations in treaties). Luria's reaction to anything else would've been significantly muted.
Attack Luria, and then get their ass kicked again? Somehow, I doubt that was tops on their list of thing to do.
What could Madina or Fissoa done in their local vicinity? All are ideas I know was expressed to various characters of theirs at certain points (yes, even the anti-lurian ones) via IC discussion. Had a civil war between each other. Invaded D'hara (resentment from their diplomatic fallout). Invaded Swordfell (Swordfell was about to invade Madina a short time prior, even). Assisted Luria against Astrum.
A staged/fake civil war, a boring/ineffectual long-distance war, a suicidal attack on Luria, or join with their former enemies to engage in unjustified attacks on their former allies. A veritable buffet of enviable options.
But no, the players themselves absolutely refused to consider any action. They could have done something; they refused.
When all your choices suck, it's kind of hard to choose between them.
The sequence of events that led to this point was not just Luria's fault. The "everyone against Luria" war kind of sucked. It destroyed the north. Everyone up there was deathly bored, only a few people ever participated, and things had decayed to the point where all it took to shatter it was a few pointed questions, and a couple people to stand up and say "we're not gonna march down there". The war caused Luria to embark on a campaign to turn the rest of the island into warring city states. The problem is that as soon as it started to actually work, Luria was so huge in comparison to their neighbors that they became an oppressive force for stagnation simply because they existed. They became just like the Astrum/Morek/Corsanctum alliance, CE/Tara/Strombran federation, post-empire Arcaea, and Sirion. Victims of their own success.
Both sides were so entrenched in the war that neither was willing to give up. Luria demanded total victory, negotiated separately with each enemy realm, with crushing terms like dismantling your realm into city-states, providing lands for Lurian colonies, appointing Lurian-approved leaders, allowing Lurian-based religions, etc. The other realms demanded group negotiations and a return to the pre-war conditions, denying Luria any concessions for the fact that the allied realms started the war, and were completely unable to make any real progress. It was a crappy war all around, only a very few people enjoyed it, but NO ONE wanted to do what it would take to stop it. You can't point a finger at any one person/realm and say "It's your fault". It's a collective guilt.