You know, I've been thinking about something, most stand users could beaten by a gun.
Here me out, stands are fast enough to stop bullets, but if you have a stand and its fighting the enemy stand, what's the enemy user gonna do if you pull a gun?
If the enemy stand does nothing it's user is dead.
If the stand stops fighting to protect its user, your stand is given an opening to attack.
But DIO and Jotaro just watch there stands fight, DIO could have one there if he just threw one of his knives at Jotaro while there stands were rushing eachother, but it's an anime, we can't end it that anticlimactically.