My point is that those new algorithms need something to learn from, and the humans that used to do the job are no longer in the game. The original corpus could be reused, but then performance will be bounded by that corpus. If better algorithms are trained on the output of worse algorithms, presumably they just emulate the performance of the worse algorithm. Where do the better algorithms get their input from, if a large scale human effort no longer exists?
But why would every translator stop working or creating new works just because machines can do the job too? I don't think computer written novels will mean people stop telling stories.
Translation is an interpretation of the best phrase to use, and has a subjective element. Imagine trying to translate jokes - it depends on your sense of humor too.