Toph never gave a hint that she wanted to isolate herself or be an eternal bachelor, she even had a crush on Sokka.
She became a hermit hated by her daughter, was I supposed to applaud that?
Speaking of Sokka, we literally get no hint of his life, all we know is that he was part of the city council or whatever at some point.
We don’t know if he married, how he died or even if he died for sure. Did he have children? None of them show up during the show.
Aang was literally erased from existence along with the Avatar legacy.
Katara and Zuko are fine I guess.