Ah the calculator fallacy; hello my old friend.
So, a calculator is a great shortcut, but it's useless for most mathematics (i.e. proof!). A lot of people assume that having a calculator means they do not need to learn mathematics - a lot of people are dead wrong!
In terms of exams being about memory, I run mine open book (i.e. students can take pre-prepped notes in). Did you know, some students still cram and forget right after the exams? Do you know, they forget even faster for courseworks?
Your argument is a good one, but let's take it further - let's rebuild education towards an employer centric training system, focusing on the use of digital tools alone. It works well, productivity skyrockets, for a few years, but the humanities die out, pure mathematics (which helped create AI) dies off, so does theoretical physics/chemistry/biology. Suddenly, innovation slows down, and you end up with stagnation.
Rather than moving us forward, such a system would lock us into place and likely create out of date workers.
At the end of the day, AI is a great tool, but so is a hammer and (like AI today), it was a good tool for solving many of the problems of its time. However, I wouldn't want to only learn how to use a hammer, otherwise how would I be replying to you right now?!?