same reason that the 3 balls in a row fh is still being taught.... but to a much lesser degree because fh is too visible.
the 1hbh, few jrs are learning the shot.... so you've got some old guys hitting the old way, teaching some other old guys with tennis elbows.... typical scene in a club.
problem is.... the old guys with tennis elbows need to handle the high balls even more than the pros (who have the footwork to avoid high hits).
mr. tennis elbow with the lazy feet, with a flawed swing path that cannot handle balls higher than chest.
you get the picture lol.