That's the "hot" period of the war. Before that there were several centuries long war of attrition between Dunedain, their allies and proxies of Sauron.
The capital city of Gondor, Osgiliath, was turned into ruins, front going straight through. And before that, the same thing happened to Minas Ithil. Those big towers next to Black Gate? Those were fortifications built by Gondor. But after Great Plague, which was probably a biological weapon of sorts, there weren't enough people to man them.
What we see in lotr, is essentially last days of war. When one side is barely clinging on, and can muster only localized offensives.
The capital city of Gondor, Osgiliath, was turned into ruins, front going straight through. And before that, the same thing happened to Minas Ithil. Those big towers next to Black Gate? Those were fortifications built by Gondor. But after Great Plague, which was probably a biological weapon of sorts, there weren't enough people to man them.
What we see in lotr, is essentially last days of war. When one side is barely clinging on, and can muster only localized offensives.