So what we've been setting up is that Purim was unlike any other encounter that Israel had with her enemies because not only did she take no plunder, but she neither burned everything up. Israel walked away from that encounter with the Persians with only her life.
To put it simply, she was already at home.
Israel was settled in the land of Persia; she had been in exile for quite a while, certainly long enough to be well-established. They were so integrated into the land that no one seemed to know that Esther was a Jew until she told them. They lived there, worked there, loved there, prayed there. Yes, in some ways, they maintained their own community apart from the Persians, but for all intents and purposes, this was home for them.
When you're established in a place, you don't have much of an interest in bringing in a whole bunch of new stuff to try to establish yourself. You don't need to. You've got your own stuff, and this is your own place, so your own place is full of your own stuff.
That also means you have plenty to offer to God. You don't need a bunch of other stuff as sacrifice or offering. You don't need extra rams; you have plenty of your own. You don't need extra wheat; you've got that, or at least, you've got access to it. You're already set up to have plenty of stuff of your own, especially when God is blessing you in a place like this, so you don't need Persia's stuff.
And you're already established here, which means you've already adopted as much of the culture as you're willing to. When you've been a people in exile this long and have set up your households so firmly in this place, you've established your rhythms and routines and priorities, so the temptations of Persia aren't so tempting to you any more. You don't need to burn everything because you're not going to fall into those traps.
Not to mention, burning everything will make you detestable to the people who have been fairly gracious to you in your captivity thus far. And God has made clear to His exiled people that they're supposed to settle themselves in this place and be gracious toward their captors and these cities. To pray for their peace and prosperity. There's no reason to be starting fires.
The situation that Israel found herself in in Persia was totally different than the other situations in which she had to fight for her life against her enemies. She fought this time as a settled people - an exiled people, yes, but a settled people in their own home. Not a Promised people moving through enemy territory. So the way that she encounters this fight is different.
The only thing Israel stands to gain or lose on Purim is her life. So at the end of the day, that's all she needs to walk away with.
Thus, she does.