I wouldn’t give up on teachers just yet. The 5-paragraph essay is probably dead as are mathematics homework assignments that are boring variations of the same problem over-and-over. The field is being cleared for new ideas and I bet some of them will prove to be very good.
How in the world did you get from "1:1 student-teacher ratio" to "ruin kids education"? AI is amazing for education. Everyone has their own teacher in their pocket.