Why? The show goes to great lengths to show you why this time should be different vs others. If an enemy has a weakness and you exploit said weakness that's how they are defeated. The night king practically ignored everyone bc Bran knew how to defeat him. Without knowledge the NK would seem and be unstoppable.
Once again I feel posts like these are just mad their version of the story in your head didn't happen
It's not about my version of the story. The show established this looming threat in the North, so dangerous and unstoppable that they had to build a giant magic wall of ice spawning half a continent to contain, its effects so world altering that they probably reshaped how seasons work in this world. And you're telling me that one dragonglass wound is enough to permanently end it? Why didn't the children do it before then, when the Others went out of control? Why didn't they were killed during the original Long Night? It''s not only anticlimatic, but it doesn't fit with what was established before. Arya can kill the leader of the army, whatever, it can have interesting consequences too, but it shouldn't istantly end a thousand years threat with one hit.