They show that you can exist without doing anything at a high level. You just regurgitate what you learnt at school and kids have to listen to you. Teachers will be replaced by computers because you can always pause them. Also we do need trainers and supervisers to ensure kids don't kill each other on the field or in the lab. However there's no need for math teachers or history teachers.
If we look the situation now. Everything has change. We have to follow the revolution. Everyday we learn new things. Day by day people created something new for the better future. Past was created for the new better future. So the schooling system. Perhaps it may be beyond than our expectations. Maybe hologram can be use in the schooling system .
The world is indeed advancing technologically and it is very likely that they will take more and more of a role in teaching. Perhaps they will become the majority role? However i think there will still be a need for teachers: For example, what if the technology goes wrong? What if there is a child that doesn't understand the technology? Also there will still be the need for other staff: eg cleaners, catering staff etc. I guess maybe in the very far future teaching staff will cease to exist but not by 2050.......Seems a bit too early.