They aren’t taught them from youth ball.
Somewhere around 15 years ago, I was asked to coach a 14-15 year old all-star team. In practice, I tried to get pitchers to back up 3rd and home when required instead of standing on the mound and to have the 1st baseman as the cutoff man. I tried to teach them no more than 2 throws on a rundown. To actually attention to a take sign so we could get a stolen base. None of it took. According to one of the parents, it was “too complicated for such young players”.
Now when I started Little League at age 9, that was stuff we practiced all the time. I repeat, I was 9. Of course, that was in the late 60s.