Marketing play to grab the money off of rich parents. There are still teachers, they are just proxied by "AI". And there will also still be teachers monitoring. And there will still be teachers for certain topics.
So it's teacherless, but with plenty of teachers.
These jacks are still in every other audio device. They were removed from phones to force BT usage, which Google needs for their profiling telemetry network and Apple for their Find my Device thing. God forbid someone turns BT off or even decides they would prefer a phone without BT entirely. There is no other reason and how people prefer to listen to music has nothing to do with the subject.