That question, at that moment, rang very hollow. In Exalted, the player characters are capital H Heroes of legends in the vein of Gilgamesh or Sun Wukong. They are the once-kings of the world who can move mountains with their bare hands and who have saved the world from tyrannical titans of old. The question being about some thing they'd have to give up in the future, rather than asking them for what great feats have they already done in pursuit of the goal felt very transactional, rather than heroic.
I understand that it was time to wrap that plot up as the game was beginning to draw to a close. Leaving that plot unresolved because the players didn't put in that much effort to fix things would be anticlimactic. Ideally, it would be communicated between the GM and the players way ahead of time. As it was now, it basically felt like throwing the character at the glory most high and tossing some coins in his face demanding "it's broken, fix it" because the players wanted it really bad.
The GM did state later that if the PCs had not offered enough their ally wouldn't have been redeemed. However, the PCs also did gamble a bit about who would have to make the sacrifice, and to make matters worse it turned out they had to sacrifice nothing since the person that drew the shortest straw was the comatosed ally, who on the count of being in that state did not volunteer to sacrifice anything. So the PCs earned a free Deus Ex Machina resolution to their arc for free.
Now imagine if the resolution was instead tied to the themes of being a tragic hero, someone larger than life, or doing impossible feats. What if Three Fates Saved would have to live the life of virtue, despite the Deathlord influences, and sacrifice her life selflessly in order to achieve redemption in death? What if she had to confront the Deathlord that held her in a binding and make him achieve peace and pass on (which would be a monumental accomplishment), or accomplish a great feat of peace, like reconciling the differences and bringing peace between the Realm and the Solars (while the party that were the Solar by now essentially wanted to conquer the Realm and subjugate them essentially). Any mighty deed that would play on the themes of "redemption", while avoiding things tied to the aspects of death and destruction.
Instead, we had Rey offering to sacrifice ever seeing her home town of Nexus (central location of the series), her father (her central relationship), and any glory she would gain in the future. Jorek offered his chance of revenge at those who have wronged him. Valeria offered giving up what makes her the most happy - her relationship with Speaks-of-Silence. Sure, any of them would be noble sacrifices and an interesting plot to explore, except the series was already drawing to a close with 13 episodes left to go, so you'd barely see any of them play out.
Worst of all, I don't think this was the GM's intended resolution for this arc. A few episodes earlier the characters were also trying to figure out how to redeem Three Fates Shadow, which eventually drove her to the coma. At that time I noticed the GM tried telegraph some solution to her problem, spelling out the clues to her condition, but the player did not pick up on it and the moment was lost.
In situations like this, especially when you're making Actual Plays, it feels important to communicate with everyone about what they want to see accomplished in the game, about how they want the game to progress, etc. This also goes both ways - sometimes the players want to communicate with the GM about what they want to see in the game, and sometimes the GM wants to talk about how some things should play out. Some might balk at that since it's a bit close to railroading, but if your intent is to improve the game, make it more fun for everyone involved and for the people watching, it might be for the best. We've done that on a number of occasions. Heck, one time we played through a module, discussed it at length, workshopped a better version of it and played through it while still having fun.
It's a fine line to thread, but it probably works for the best when everyone's involved in the process and there is a back-and-forth on how things should go down. It might not be for everyone or every game, but it can make some key moments land better.
Conclusions
When you have a long story arc in a game you hope the payoff would be worth the long buildup. The longer and more epic the arc the more satisfying payoff you need for it to feel rewarding. However, if the resolution hinges on what the players do, it might be worth having a chat about it ahead of time so everyone would be onboard with what would produce the most satisfying ending to that story. This is especially important when producing media for other people to consume.
If you don't plan ahead, together between the GM and the players, you might just have to ask your characters "what are you willing to pay in the future for a resolution to this plot in the present?"...
