TCP doesn't know anything about route failure or rerouting. All it does is handle a few dropped or reordered packets here and there.

In principle, you can have systems that very quickly route around damage like this, but in practice it happens so rarely that it's not worth it for consumer ISPs. I think it should exist, but the ISP space is so burdened with red tape that the only way anyone could compete with it was literally to start a rocket ship company and launch a bunch of satellites.