action 'switch_theme' not firing

In my theme I expect switch_theme to be enacted when I change away from my theme; however, it is never firing; I even put in a nonsense function to call hoping to get an error, with nothing.

function my_deinit () {
  echo "<script>console.log('In my_deinit');</script>";
  my_do_caps( 'remove_cap' );
  my_clear_taxonomy( 'persondepartments' );
}
add_action('switch_theme', 'my_deinitzzz');