I'm not sure this explanation holds water. Plenty of experts have managed to keep their beginner's mind, and they are often the very best in their field. In lots of fields, keeping an open, learning mind is an important part of being considered a leader, so it should never be 'optimized away'.

I'm also not saying anything about empathizing, even just an intellectual appreciation for somebody learning your matter should be enough to not lash out and be a dick. And it surprised me that there are so many that fail to bring up even that little appreciation.