The Aes Sedai and the White Tower seems to me like it was almost in stasis during the entire third age. They didn't learn anything new, they didn't discover anything cool, they didn't do research. All they did was pine after the good old days of the second age, and that blinded them to the...
It seems to me, that like others said farther behind, that the AS started severing men out of sheer necessity, and then kept doing it because it's what they had always done. I also think that Far Madding type places or permanent shields would have been a far better choice. That would have done...