Motivating students to learn is not at all a solved task. And arguably a harder one too. Even the ~2010 "Google and grit" self-teaching is enough to outperform public education - but most students don't have the motivation to pull that off in practice. They have the opportunity, but that matters little if they don't use it.
Mastery of arithmetic involves memorizing lots of heuristic rules that aren’t particularly insightful about, or are outright conflicting with, the structure of math, and learning the structure of math first slows your ability to do arithmetic.
I don’t think any school hands first graders calculators and asks them to never learn arithmetic. But I see no need once you’re doing algebra to be focusing your time on long division or multiplication. These are irrelevant distractions from algebra, time spent and points lost on arithmetic details is a waste of cognition and doesn’t help. This becomes increasingly true through calculus, linear algebra, until you get to real math courses where a calculator is pointless because arithmetic doesn’t even show up.
Long division, at least conceptually, is also present in algebra and partial fractions.
Everything builds on everything else.
Some kids really enjoy learning. Never mind merely solving an educational assessments problem, personalized learning seems like it has the potential to unlock a lot of intellect across the population. And yet.
If anything, if someone is looking for an AI proof job while not wanting to do something braindead, teaching might be one of the good jobs that may get more competitive.