When I took math in elementary school, in the 80s, it was self paced. You really didn't get an F, you just kept studying a topic until you could pass it at 90%. On the other side, if you could pass a pre-test, you could skip the topic. It really enjoyed, because I could learn some topics in an hour, which would normally be 10 hours of boring instruction.
It was a little more work for the teachers, since the system admitted that kids were at a variety of levels, but it was roughly a normal distribution, where a whole classroom of kids were on normal pace, some were a little bit ahead or behind, and a few were way ahead or behind. It seems like adaptive learning software could make this even easier.
You say teachers could do it in the 80's. Montessori could do it 100 years ago. I don't think the problem is lack of technology, it's that the principles of education have changed. Software won't fix that.
It was a little more work for the teachers, since the system admitted that kids were at a variety of levels, but it was roughly a normal distribution, where a whole classroom of kids were on normal pace, some were a little bit ahead or behind, and a few were way ahead or behind. It seems like adaptive learning software could make this even easier.