This is definitely what's going to happen. But there is still a problem - people (not just children) are fundamentally lazy and put things off. People always leave assignments until the last minute. I used to smoothly transition from "I've got plenty of time, no need to start" to "there's not enough time to do it, there's no point starting".
They will 100% just use AI for the whole year and then panic and fail the exam when the time comes.
So I think not only will we see more invigilated exams, but they'll become more frequent and shorter. Which I would say is a good thing anyway. I always hated learning a whole year of stuff for a 3 hour exam.