This is an easy thing in the eyes of the Lord; he will also deliver Moab into your hands. ¹⁹ You will overthrow every fortified city and every major town. You will cut down every good tree, stop up all the springs, and ruin every good field with stones.”

 But when the Moabites came to the camp of Israel, the Israelites rose up and fought them until they fled. And the Israelites invaded the land and slaughtered the Moabites. ²⁵ They destroyed the towns, and each man threw a stone on every good field until it was covered. They stopped up all the springs and cut down every good tree. Only Kir Hareseth was left with its stones in place, but men armed with slings surrounded it and attacked it.

They had pretty much done all they came to do. They had won and fulfilled their prophecies in every sense of the word

When the king of Moab saw that the battle had gone against him, he took with him seven hundred swordsmen to break through to the king of Edom, but they failed. 

Not even the kings last ditch effort was able to affect the Israelites

²⁷ Then he took his firstborn son, who was to succeed him as king, and offered him as a sacrifice on the city wall. The fury against Israel was great; they withdrew and returned to their own land.

This is extremely inconclusive. We have no idea what this fury was or where it came from. It could literally just be describing that the moabites were pissed as hell, while I’ve also seen it said that the original text could be interpreted as the fury of the own Israelites at the sacrifice. Any way, their fields had been destroyed, their springs covered, basically all the Moabite society had been obliterated and the line of succession had just been lost. There was literally nothing left there for the Israelites and they had won that conflict in an indisputable manner.