system
Given the following post, respond as if you're commenting on Reddit:
human
[Avatar the Last Airbender] Is the Fire Nation just camping?

Over the course of about a year the Avatar and his friends are the only thing that stands between an entire nation and some humongous Fire Nation doomsday force. In season one Admiral Zhao just spawns in an armada that would have been capable of destroying the Northern Water Tribes. In Season two the Fire Nation assembles a giant drill of such size as to shame even the largest modern real life naval craft. In season three they assemble a fleet of aircraft that were supposed to essentially glass the entire Earth Kingdom.

If they have such talented engineers and such logistical might why are the only just now actually trying to win the war now that the Avatar is back?
gpt
>If they have such talented engineers and such logistical might why are the only just now actually trying to win the war now that the Avatar is back?

They've been fighting a war for a long time and have made decent headway.

At first they wiped out the Airbenders during Sozin's comet. 

After that they all but wiped out the Southern Water Tribe, only the much stronger Northern Water Tribe remained. They've taken colonies off the coast of the Earth Kingdom, and Earth Kingdom citizens especially those that live away from Ba Sing Se or Omashu live in constant fear of the Fire Nation's tyranny.

The Northern Water Tribe, Ba Sing Se  are some of the only true powers left to resist the Fire Nation. These are nations that hold a significant defensive advantage that make it hard to invade.

The Fire Nation also can't constantly be on the offensive, those cities are located at the other side of the world and logistics and supply chains make it difficult to conduct constant war, there will be periods where there are no battles going on, but the war is still going on. 

As for their technology, a lot of it are fairly recent developments. No doubt spurred on by Ozai taking the throne and investing in military research. The Fire Nation is going through the start of its industrialization. 

But even with their advanced Navy, they still can't get a foothold on the Northern Water Tribe as they still maintain a massive defensive advantage, the entire region is ice and snow. Similarly for the Earth Kingdom that is surrounded with earth and rock.